raid5.c 179.7 KB
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/*
 * raid5.c : Multiple Devices driver for Linux
 *	   Copyright (C) 1996, 1997 Ingo Molnar, Miguel de Icaza, Gadi Oxman
 *	   Copyright (C) 1999, 2000 Ingo Molnar
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 *	   Copyright (C) 2002, 2003 H. Peter Anvin
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 *
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 * RAID-4/5/6 management functions.
 * Thanks to Penguin Computing for making the RAID-6 development possible
 * by donating a test server!
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 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * You should have received a copy of the GNU General Public License
 * (for example /usr/src/linux/COPYING); if not, write to the Free
 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

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/*
 * BITMAP UNPLUGGING:
 *
 * The sequencing for updating the bitmap reliably is a little
 * subtle (and I got it wrong the first time) so it deserves some
 * explanation.
 *
 * We group bitmap updates into batches.  Each batch has a number.
 * We may write out several batches at once, but that isn't very important.
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 * conf->seq_write is the number of the last batch successfully written.
 * conf->seq_flush is the number of the last batch that was closed to
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 *    new additions.
 * When we discover that we will need to write to any block in a stripe
 * (in add_stripe_bio) we update the in-memory bitmap and record in sh->bm_seq
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 * the number of the batch it will be in. This is seq_flush+1.
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 * When we are ready to do a write, if that batch hasn't been written yet,
 *   we plug the array and queue the stripe for later.
 * When an unplug happens, we increment bm_flush, thus closing the current
 *   batch.
 * When we notice that bm_flush > bm_write, we write out all pending updates
 * to the bitmap, and advance bm_write to where bm_flush was.
 * This may occasionally write a bit out twice, but is sure never to
 * miss any bits.
 */
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#include <linux/blkdev.h>
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#include <linux/kthread.h>
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#include <linux/raid/pq.h>
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#include <linux/async_tx.h>
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#include <linux/module.h>
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#include <linux/async.h>
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#include <linux/seq_file.h>
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#include <linux/cpu.h>
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#include <linux/slab.h>
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#include <linux/ratelimit.h>
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#include <trace/events/block.h>

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#include "md.h"
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#include "raid5.h"
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#include "raid0.h"
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#include "bitmap.h"
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/*
 * Stripe cache
 */

#define NR_STRIPES		256
#define STRIPE_SIZE		PAGE_SIZE
#define STRIPE_SHIFT		(PAGE_SHIFT - 9)
#define STRIPE_SECTORS		(STRIPE_SIZE>>9)
#define	IO_THRESHOLD		1
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#define BYPASS_THRESHOLD	1
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#define NR_HASH			(PAGE_SIZE / sizeof(struct hlist_head))
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#define HASH_MASK		(NR_HASH - 1)

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static inline struct hlist_head *stripe_hash(struct r5conf *conf, sector_t sect)
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{
	int hash = (sect >> STRIPE_SHIFT) & HASH_MASK;
	return &conf->stripe_hashtbl[hash];
}
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/* bio's attached to a stripe+device for I/O are linked together in bi_sector
 * order without overlap.  There may be several bio's per stripe+device, and
 * a bio could span several devices.
 * When walking this list for a particular stripe+device, we must never proceed
 * beyond a bio that extends past this device, as the next bio might no longer
 * be valid.
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 * This function is used to determine the 'next' bio in the list, given the sector
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 * of the current stripe+device
 */
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static inline struct bio *r5_next_bio(struct bio *bio, sector_t sector)
{
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	int sectors = bio_sectors(bio);
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	if (bio->bi_sector + sectors < sector + STRIPE_SECTORS)
		return bio->bi_next;
	else
		return NULL;
}
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/*
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 * We maintain a biased count of active stripes in the bottom 16 bits of
 * bi_phys_segments, and a count of processed stripes in the upper 16 bits
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 */
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static inline int raid5_bi_processed_stripes(struct bio *bio)
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{
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	atomic_t *segments = (atomic_t *)&bio->bi_phys_segments;
	return (atomic_read(segments) >> 16) & 0xffff;
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}

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static inline int raid5_dec_bi_active_stripes(struct bio *bio)
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{
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	atomic_t *segments = (atomic_t *)&bio->bi_phys_segments;
	return atomic_sub_return(1, segments) & 0xffff;
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}

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static inline void raid5_inc_bi_active_stripes(struct bio *bio)
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{
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	atomic_t *segments = (atomic_t *)&bio->bi_phys_segments;
	atomic_inc(segments);
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}

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static inline void raid5_set_bi_processed_stripes(struct bio *bio,
	unsigned int cnt)
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{
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	atomic_t *segments = (atomic_t *)&bio->bi_phys_segments;
	int old, new;
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	do {
		old = atomic_read(segments);
		new = (old & 0xffff) | (cnt << 16);
	} while (atomic_cmpxchg(segments, old, new) != old);
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}

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static inline void raid5_set_bi_stripes(struct bio *bio, unsigned int cnt)
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{
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	atomic_t *segments = (atomic_t *)&bio->bi_phys_segments;
	atomic_set(segments, cnt);
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}

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/* Find first data disk in a raid6 stripe */
static inline int raid6_d0(struct stripe_head *sh)
{
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	if (sh->ddf_layout)
		/* ddf always start from first device */
		return 0;
	/* md starts just after Q block */
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	if (sh->qd_idx == sh->disks - 1)
		return 0;
	else
		return sh->qd_idx + 1;
}
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static inline int raid6_next_disk(int disk, int raid_disks)
{
	disk++;
	return (disk < raid_disks) ? disk : 0;
}
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/* When walking through the disks in a raid5, starting at raid6_d0,
 * We need to map each disk to a 'slot', where the data disks are slot
 * 0 .. raid_disks-3, the parity disk is raid_disks-2 and the Q disk
 * is raid_disks-1.  This help does that mapping.
 */
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static int raid6_idx_to_slot(int idx, struct stripe_head *sh,
			     int *count, int syndrome_disks)
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{
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	int slot = *count;
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	if (sh->ddf_layout)
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		(*count)++;
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	if (idx == sh->pd_idx)
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		return syndrome_disks;
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	if (idx == sh->qd_idx)
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		return syndrome_disks + 1;
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	if (!sh->ddf_layout)
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		(*count)++;
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	return slot;
}

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static void return_io(struct bio *return_bi)
{
	struct bio *bi = return_bi;
	while (bi) {

		return_bi = bi->bi_next;
		bi->bi_next = NULL;
		bi->bi_size = 0;
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		bio_endio(bi, 0);
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		bi = return_bi;
	}
}

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static void print_raid5_conf (struct r5conf *conf);
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static int stripe_operations_active(struct stripe_head *sh)
{
	return sh->check_state || sh->reconstruct_state ||
	       test_bit(STRIPE_BIOFILL_RUN, &sh->state) ||
	       test_bit(STRIPE_COMPUTE_RUN, &sh->state);
}

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static void do_release_stripe(struct r5conf *conf, struct stripe_head *sh)
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{
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	BUG_ON(!list_empty(&sh->lru));
	BUG_ON(atomic_read(&conf->active_stripes)==0);
	if (test_bit(STRIPE_HANDLE, &sh->state)) {
		if (test_bit(STRIPE_DELAYED, &sh->state) &&
		    !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
			list_add_tail(&sh->lru, &conf->delayed_list);
		else if (test_bit(STRIPE_BIT_DELAY, &sh->state) &&
			   sh->bm_seq - conf->seq_write > 0)
			list_add_tail(&sh->lru, &conf->bitmap_list);
		else {
			clear_bit(STRIPE_DELAYED, &sh->state);
			clear_bit(STRIPE_BIT_DELAY, &sh->state);
			list_add_tail(&sh->lru, &conf->handle_list);
		}
		md_wakeup_thread(conf->mddev->thread);
	} else {
		BUG_ON(stripe_operations_active(sh));
		if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
			if (atomic_dec_return(&conf->preread_active_stripes)
			    < IO_THRESHOLD)
				md_wakeup_thread(conf->mddev->thread);
		atomic_dec(&conf->active_stripes);
		if (!test_bit(STRIPE_EXPANDING, &sh->state)) {
			list_add_tail(&sh->lru, &conf->inactive_list);
			wake_up(&conf->wait_for_stripe);
			if (conf->retry_read_aligned)
				md_wakeup_thread(conf->mddev->thread);
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		}
	}
}
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static void __release_stripe(struct r5conf *conf, struct stripe_head *sh)
{
	if (atomic_dec_and_test(&sh->count))
		do_release_stripe(conf, sh);
}

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static void release_stripe(struct stripe_head *sh)
{
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	struct r5conf *conf = sh->raid_conf;
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	unsigned long flags;
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	local_irq_save(flags);
	if (atomic_dec_and_lock(&sh->count, &conf->device_lock)) {
		do_release_stripe(conf, sh);
		spin_unlock(&conf->device_lock);
	}
	local_irq_restore(flags);
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}

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static inline void remove_hash(struct stripe_head *sh)
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{
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	pr_debug("remove_hash(), stripe %llu\n",
		(unsigned long long)sh->sector);
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	hlist_del_init(&sh->hash);
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}

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static inline void insert_hash(struct r5conf *conf, struct stripe_head *sh)
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{
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	struct hlist_head *hp = stripe_hash(conf, sh->sector);
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	pr_debug("insert_hash(), stripe %llu\n",
		(unsigned long long)sh->sector);
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	hlist_add_head(&sh->hash, hp);
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}


/* find an idle stripe, make sure it is unhashed, and return it. */
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static struct stripe_head *get_free_stripe(struct r5conf *conf)
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{
	struct stripe_head *sh = NULL;
	struct list_head *first;

	if (list_empty(&conf->inactive_list))
		goto out;
	first = conf->inactive_list.next;
	sh = list_entry(first, struct stripe_head, lru);
	list_del_init(first);
	remove_hash(sh);
	atomic_inc(&conf->active_stripes);
out:
	return sh;
}

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static void shrink_buffers(struct stripe_head *sh)
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{
	struct page *p;
	int i;
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	int num = sh->raid_conf->pool_size;
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	for (i = 0; i < num ; i++) {
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		p = sh->dev[i].page;
		if (!p)
			continue;
		sh->dev[i].page = NULL;
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		put_page(p);
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	}
}

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static int grow_buffers(struct stripe_head *sh)
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{
	int i;
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	int num = sh->raid_conf->pool_size;
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	for (i = 0; i < num; i++) {
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		struct page *page;

		if (!(page = alloc_page(GFP_KERNEL))) {
			return 1;
		}
		sh->dev[i].page = page;
	}
	return 0;
}

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static void raid5_build_block(struct stripe_head *sh, int i, int previous);
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static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
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			    struct stripe_head *sh);
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static void init_stripe(struct stripe_head *sh, sector_t sector, int previous)
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{
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	struct r5conf *conf = sh->raid_conf;
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	int i;
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	BUG_ON(atomic_read(&sh->count) != 0);
	BUG_ON(test_bit(STRIPE_HANDLE, &sh->state));
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	BUG_ON(stripe_operations_active(sh));
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	pr_debug("init_stripe called, stripe %llu\n",
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		(unsigned long long)sh->sector);

	remove_hash(sh);
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	sh->generation = conf->generation - previous;
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	sh->disks = previous ? conf->previous_raid_disks : conf->raid_disks;
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	sh->sector = sector;
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	stripe_set_idx(sector, conf, previous, sh);
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	sh->state = 0;

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	for (i = sh->disks; i--; ) {
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		struct r5dev *dev = &sh->dev[i];

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		if (dev->toread || dev->read || dev->towrite || dev->written ||
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		    test_bit(R5_LOCKED, &dev->flags)) {
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			printk(KERN_ERR "sector=%llx i=%d %p %p %p %p %d\n",
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			       (unsigned long long)sh->sector, i, dev->toread,
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			       dev->read, dev->towrite, dev->written,
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			       test_bit(R5_LOCKED, &dev->flags));
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			WARN_ON(1);
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		}
		dev->flags = 0;
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		raid5_build_block(sh, i, previous);
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	}
	insert_hash(conf, sh);
}

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static struct stripe_head *__find_stripe(struct r5conf *conf, sector_t sector,
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					 short generation)
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{
	struct stripe_head *sh;

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	pr_debug("__find_stripe, sector %llu\n", (unsigned long long)sector);
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	hlist_for_each_entry(sh, stripe_hash(conf, sector), hash)
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		if (sh->sector == sector && sh->generation == generation)
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			return sh;
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	pr_debug("__stripe %llu not in cache\n", (unsigned long long)sector);
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	return NULL;
}

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/*
 * Need to check if array has failed when deciding whether to:
 *  - start an array
 *  - remove non-faulty devices
 *  - add a spare
 *  - allow a reshape
 * This determination is simple when no reshape is happening.
 * However if there is a reshape, we need to carefully check
 * both the before and after sections.
 * This is because some failed devices may only affect one
 * of the two sections, and some non-in_sync devices may
 * be insync in the section most affected by failed devices.
 */
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static int calc_degraded(struct r5conf *conf)
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{
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	int degraded, degraded2;
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	int i;

	rcu_read_lock();
	degraded = 0;
	for (i = 0; i < conf->previous_raid_disks; i++) {
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		struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
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		if (rdev && test_bit(Faulty, &rdev->flags))
			rdev = rcu_dereference(conf->disks[i].replacement);
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		if (!rdev || test_bit(Faulty, &rdev->flags))
			degraded++;
		else if (test_bit(In_sync, &rdev->flags))
			;
		else
			/* not in-sync or faulty.
			 * If the reshape increases the number of devices,
			 * this is being recovered by the reshape, so
			 * this 'previous' section is not in_sync.
			 * If the number of devices is being reduced however,
			 * the device can only be part of the array if
			 * we are reverting a reshape, so this section will
			 * be in-sync.
			 */
			if (conf->raid_disks >= conf->previous_raid_disks)
				degraded++;
	}
	rcu_read_unlock();
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	if (conf->raid_disks == conf->previous_raid_disks)
		return degraded;
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	rcu_read_lock();
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	degraded2 = 0;
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	for (i = 0; i < conf->raid_disks; i++) {
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		struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
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		if (rdev && test_bit(Faulty, &rdev->flags))
			rdev = rcu_dereference(conf->disks[i].replacement);
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		if (!rdev || test_bit(Faulty, &rdev->flags))
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			degraded2++;
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		else if (test_bit(In_sync, &rdev->flags))
			;
		else
			/* not in-sync or faulty.
			 * If reshape increases the number of devices, this
			 * section has already been recovered, else it
			 * almost certainly hasn't.
			 */
			if (conf->raid_disks <= conf->previous_raid_disks)
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				degraded2++;
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	}
	rcu_read_unlock();
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	if (degraded2 > degraded)
		return degraded2;
	return degraded;
}

static int has_failed(struct r5conf *conf)
{
	int degraded;

	if (conf->mddev->reshape_position == MaxSector)
		return conf->mddev->degraded > conf->max_degraded;

	degraded = calc_degraded(conf);
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	if (degraded > conf->max_degraded)
		return 1;
	return 0;
}

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static struct stripe_head *
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get_active_stripe(struct r5conf *conf, sector_t sector,
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		  int previous, int noblock, int noquiesce)
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{
	struct stripe_head *sh;

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	pr_debug("get_stripe, sector %llu\n", (unsigned long long)sector);
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	spin_lock_irq(&conf->device_lock);

	do {
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		wait_event_lock_irq(conf->wait_for_stripe,
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				    conf->quiesce == 0 || noquiesce,
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				    conf->device_lock);
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		sh = __find_stripe(conf, sector, conf->generation - previous);
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		if (!sh) {
			if (!conf->inactive_blocked)
				sh = get_free_stripe(conf);
			if (noblock && sh == NULL)
				break;
			if (!sh) {
				conf->inactive_blocked = 1;
				wait_event_lock_irq(conf->wait_for_stripe,
						    !list_empty(&conf->inactive_list) &&
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						    (atomic_read(&conf->active_stripes)
						     < (conf->max_nr_stripes *3/4)
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						     || !conf->inactive_blocked),
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						    conf->device_lock);
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				conf->inactive_blocked = 0;
			} else
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				init_stripe(sh, sector, previous);
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		} else {
			if (atomic_read(&sh->count)) {
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				BUG_ON(!list_empty(&sh->lru)
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				    && !test_bit(STRIPE_EXPANDING, &sh->state)
				    && !test_bit(STRIPE_ON_UNPLUG_LIST, &sh->state));
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			} else {
				if (!test_bit(STRIPE_HANDLE, &sh->state))
					atomic_inc(&conf->active_stripes);
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				if (list_empty(&sh->lru) &&
				    !test_bit(STRIPE_EXPANDING, &sh->state))
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					BUG();
				list_del_init(&sh->lru);
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			}
		}
	} while (sh == NULL);

	if (sh)
		atomic_inc(&sh->count);

	spin_unlock_irq(&conf->device_lock);
	return sh;
}

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/* Determine if 'data_offset' or 'new_data_offset' should be used
 * in this stripe_head.
 */
static int use_new_offset(struct r5conf *conf, struct stripe_head *sh)
{
	sector_t progress = conf->reshape_progress;
	/* Need a memory barrier to make sure we see the value
	 * of conf->generation, or ->data_offset that was set before
	 * reshape_progress was updated.
	 */
	smp_rmb();
	if (progress == MaxSector)
		return 0;
	if (sh->generation == conf->generation - 1)
		return 0;
	/* We are in a reshape, and this is a new-generation stripe,
	 * so use new_data_offset.
	 */
	return 1;
}

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static void
raid5_end_read_request(struct bio *bi, int error);
static void
raid5_end_write_request(struct bio *bi, int error);
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static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
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{
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	struct r5conf *conf = sh->raid_conf;
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	int i, disks = sh->disks;

	might_sleep();

	for (i = disks; i--; ) {
		int rw;
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		int replace_only = 0;
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		struct bio *bi, *rbi;
		struct md_rdev *rdev, *rrdev = NULL;
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		if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags)) {
			if (test_and_clear_bit(R5_WantFUA, &sh->dev[i].flags))
				rw = WRITE_FUA;
			else
				rw = WRITE;
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			if (test_bit(R5_Discard, &sh->dev[i].flags))
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				rw |= REQ_DISCARD;
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		} else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags))
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			rw = READ;
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		else if (test_and_clear_bit(R5_WantReplace,
					    &sh->dev[i].flags)) {
			rw = WRITE;
			replace_only = 1;
		} else
563
			continue;
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Shaohua Li 已提交
564 565
		if (test_and_clear_bit(R5_SyncIO, &sh->dev[i].flags))
			rw |= REQ_SYNC;
566 567

		bi = &sh->dev[i].req;
568
		rbi = &sh->dev[i].rreq; /* For writing to replacement */
569 570

		bi->bi_rw = rw;
571 572
		rbi->bi_rw = rw;
		if (rw & WRITE) {
573
			bi->bi_end_io = raid5_end_write_request;
574 575
			rbi->bi_end_io = raid5_end_write_request;
		} else
576 577 578
			bi->bi_end_io = raid5_end_read_request;

		rcu_read_lock();
579
		rrdev = rcu_dereference(conf->disks[i].replacement);
580 581 582 583 584 585
		smp_mb(); /* Ensure that if rrdev is NULL, rdev won't be */
		rdev = rcu_dereference(conf->disks[i].rdev);
		if (!rdev) {
			rdev = rrdev;
			rrdev = NULL;
		}
586 587 588
		if (rw & WRITE) {
			if (replace_only)
				rdev = NULL;
589 590 591
			if (rdev == rrdev)
				/* We raced and saw duplicates */
				rrdev = NULL;
592
		} else {
593
			if (test_bit(R5_ReadRepl, &sh->dev[i].flags) && rrdev)
594 595 596
				rdev = rrdev;
			rrdev = NULL;
		}
597

598 599 600 601
		if (rdev && test_bit(Faulty, &rdev->flags))
			rdev = NULL;
		if (rdev)
			atomic_inc(&rdev->nr_pending);
602 603 604 605
		if (rrdev && test_bit(Faulty, &rrdev->flags))
			rrdev = NULL;
		if (rrdev)
			atomic_inc(&rrdev->nr_pending);
606 607
		rcu_read_unlock();

608
		/* We have already checked bad blocks for reads.  Now
609 610
		 * need to check for writes.  We never accept write errors
		 * on the replacement, so we don't to check rrdev.
611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630
		 */
		while ((rw & WRITE) && rdev &&
		       test_bit(WriteErrorSeen, &rdev->flags)) {
			sector_t first_bad;
			int bad_sectors;
			int bad = is_badblock(rdev, sh->sector, STRIPE_SECTORS,
					      &first_bad, &bad_sectors);
			if (!bad)
				break;

			if (bad < 0) {
				set_bit(BlockedBadBlocks, &rdev->flags);
				if (!conf->mddev->external &&
				    conf->mddev->flags) {
					/* It is very unlikely, but we might
					 * still need to write out the
					 * bad block log - better give it
					 * a chance*/
					md_check_recovery(conf->mddev);
				}
631 632 633 634 635 636
				/*
				 * Because md_wait_for_blocked_rdev
				 * will dec nr_pending, we must
				 * increment it first.
				 */
				atomic_inc(&rdev->nr_pending);
637 638 639 640 641 642 643 644
				md_wait_for_blocked_rdev(rdev, conf->mddev);
			} else {
				/* Acknowledged bad block - skip the write */
				rdev_dec_pending(rdev, conf->mddev);
				rdev = NULL;
			}
		}

645
		if (rdev) {
646 647
			if (s->syncing || s->expanding || s->expanded
			    || s->replacing)
648 649
				md_sync_acct(rdev->bdev, STRIPE_SECTORS);

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Dan Williams 已提交
650 651
			set_bit(STRIPE_IO_STARTED, &sh->state);

652 653
			bi->bi_bdev = rdev->bdev;
			pr_debug("%s: for %llu schedule op %ld on disc %d\n",
654
				__func__, (unsigned long long)sh->sector,
655 656
				bi->bi_rw, i);
			atomic_inc(&sh->count);
657 658 659 660 661 662
			if (use_new_offset(conf, sh))
				bi->bi_sector = (sh->sector
						 + rdev->new_data_offset);
			else
				bi->bi_sector = (sh->sector
						 + rdev->data_offset);
663 664 665
			if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
				bi->bi_rw |= REQ_FLUSH;

666 667 668 669 670 671
			bi->bi_flags = 1 << BIO_UPTODATE;
			bi->bi_idx = 0;
			bi->bi_io_vec[0].bv_len = STRIPE_SIZE;
			bi->bi_io_vec[0].bv_offset = 0;
			bi->bi_size = STRIPE_SIZE;
			bi->bi_next = NULL;
672 673
			if (rrdev)
				set_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags);
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674 675 676
			trace_block_bio_remap(bdev_get_queue(bi->bi_bdev),
					      bi, disk_devt(conf->mddev->gendisk),
					      sh->dev[i].sector);
677
			generic_make_request(bi);
678 679
		}
		if (rrdev) {
680 681
			if (s->syncing || s->expanding || s->expanded
			    || s->replacing)
682 683 684 685 686 687 688 689 690 691
				md_sync_acct(rrdev->bdev, STRIPE_SECTORS);

			set_bit(STRIPE_IO_STARTED, &sh->state);

			rbi->bi_bdev = rrdev->bdev;
			pr_debug("%s: for %llu schedule op %ld on "
				 "replacement disc %d\n",
				__func__, (unsigned long long)sh->sector,
				rbi->bi_rw, i);
			atomic_inc(&sh->count);
692 693 694 695 696 697
			if (use_new_offset(conf, sh))
				rbi->bi_sector = (sh->sector
						  + rrdev->new_data_offset);
			else
				rbi->bi_sector = (sh->sector
						  + rrdev->data_offset);
698 699 700 701 702 703
			rbi->bi_flags = 1 << BIO_UPTODATE;
			rbi->bi_idx = 0;
			rbi->bi_io_vec[0].bv_len = STRIPE_SIZE;
			rbi->bi_io_vec[0].bv_offset = 0;
			rbi->bi_size = STRIPE_SIZE;
			rbi->bi_next = NULL;
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NeilBrown 已提交
704 705 706
			trace_block_bio_remap(bdev_get_queue(rbi->bi_bdev),
					      rbi, disk_devt(conf->mddev->gendisk),
					      sh->dev[i].sector);
707 708 709
			generic_make_request(rbi);
		}
		if (!rdev && !rrdev) {
710
			if (rw & WRITE)
711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727
				set_bit(STRIPE_DEGRADED, &sh->state);
			pr_debug("skip op %ld on disc %d for sector %llu\n",
				bi->bi_rw, i, (unsigned long long)sh->sector);
			clear_bit(R5_LOCKED, &sh->dev[i].flags);
			set_bit(STRIPE_HANDLE, &sh->state);
		}
	}
}

static struct dma_async_tx_descriptor *
async_copy_data(int frombio, struct bio *bio, struct page *page,
	sector_t sector, struct dma_async_tx_descriptor *tx)
{
	struct bio_vec *bvl;
	struct page *bio_page;
	int i;
	int page_offset;
728
	struct async_submit_ctl submit;
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	enum async_tx_flags flags = 0;
730 731 732 733 734

	if (bio->bi_sector >= sector)
		page_offset = (signed)(bio->bi_sector - sector) * 512;
	else
		page_offset = (signed)(sector - bio->bi_sector) * -512;
735

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736 737 738 739
	if (frombio)
		flags |= ASYNC_TX_FENCE;
	init_async_submit(&submit, flags, tx, NULL, NULL, NULL);

740
	bio_for_each_segment(bvl, bio, i) {
741
		int len = bvl->bv_len;
742 743 744 745 746 747 748 749 750 751 752 753 754 755 756
		int clen;
		int b_offset = 0;

		if (page_offset < 0) {
			b_offset = -page_offset;
			page_offset += b_offset;
			len -= b_offset;
		}

		if (len > 0 && page_offset + len > STRIPE_SIZE)
			clen = STRIPE_SIZE - page_offset;
		else
			clen = len;

		if (clen > 0) {
757 758
			b_offset += bvl->bv_offset;
			bio_page = bvl->bv_page;
759 760
			if (frombio)
				tx = async_memcpy(page, bio_page, page_offset,
761
						  b_offset, clen, &submit);
762 763
			else
				tx = async_memcpy(bio_page, page, b_offset,
764
						  page_offset, clen, &submit);
765
		}
766 767 768
		/* chain the operations */
		submit.depend_tx = tx;

769 770 771 772 773 774 775 776 777 778 779 780
		if (clen < len) /* hit end of page */
			break;
		page_offset +=  len;
	}

	return tx;
}

static void ops_complete_biofill(void *stripe_head_ref)
{
	struct stripe_head *sh = stripe_head_ref;
	struct bio *return_bi = NULL;
781
	int i;
782

783
	pr_debug("%s: stripe %llu\n", __func__,
784 785 786 787 788 789 790
		(unsigned long long)sh->sector);

	/* clear completed biofills */
	for (i = sh->disks; i--; ) {
		struct r5dev *dev = &sh->dev[i];

		/* acknowledge completion of a biofill operation */
791 792
		/* and check if we need to reply to a read request,
		 * new R5_Wantfill requests are held off until
793
		 * !STRIPE_BIOFILL_RUN
794 795
		 */
		if (test_and_clear_bit(R5_Wantfill, &dev->flags)) {
796 797 798 799 800 801 802 803
			struct bio *rbi, *rbi2;

			BUG_ON(!dev->read);
			rbi = dev->read;
			dev->read = NULL;
			while (rbi && rbi->bi_sector <
				dev->sector + STRIPE_SECTORS) {
				rbi2 = r5_next_bio(rbi, dev->sector);
804
				if (!raid5_dec_bi_active_stripes(rbi)) {
805 806 807 808 809 810 811
					rbi->bi_next = return_bi;
					return_bi = rbi;
				}
				rbi = rbi2;
			}
		}
	}
812
	clear_bit(STRIPE_BIOFILL_RUN, &sh->state);
813 814 815

	return_io(return_bi);

816
	set_bit(STRIPE_HANDLE, &sh->state);
817 818 819 820 821 822
	release_stripe(sh);
}

static void ops_run_biofill(struct stripe_head *sh)
{
	struct dma_async_tx_descriptor *tx = NULL;
823
	struct async_submit_ctl submit;
824 825
	int i;

826
	pr_debug("%s: stripe %llu\n", __func__,
827 828 829 830 831 832
		(unsigned long long)sh->sector);

	for (i = sh->disks; i--; ) {
		struct r5dev *dev = &sh->dev[i];
		if (test_bit(R5_Wantfill, &dev->flags)) {
			struct bio *rbi;
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Shaohua Li 已提交
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			spin_lock_irq(&sh->stripe_lock);
834 835
			dev->read = rbi = dev->toread;
			dev->toread = NULL;
S
Shaohua Li 已提交
836
			spin_unlock_irq(&sh->stripe_lock);
837 838 839 840 841 842 843 844 845 846
			while (rbi && rbi->bi_sector <
				dev->sector + STRIPE_SECTORS) {
				tx = async_copy_data(0, rbi, dev->page,
					dev->sector, tx);
				rbi = r5_next_bio(rbi, dev->sector);
			}
		}
	}

	atomic_inc(&sh->count);
847 848
	init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_biofill, sh, NULL);
	async_trigger_callback(&submit);
849 850
}

851
static void mark_target_uptodate(struct stripe_head *sh, int target)
852
{
853
	struct r5dev *tgt;
854

855 856
	if (target < 0)
		return;
857

858
	tgt = &sh->dev[target];
859 860 861
	set_bit(R5_UPTODATE, &tgt->flags);
	BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
	clear_bit(R5_Wantcompute, &tgt->flags);
862 863
}

864
static void ops_complete_compute(void *stripe_head_ref)
865 866 867
{
	struct stripe_head *sh = stripe_head_ref;

868
	pr_debug("%s: stripe %llu\n", __func__,
869 870
		(unsigned long long)sh->sector);

871
	/* mark the computed target(s) as uptodate */
872
	mark_target_uptodate(sh, sh->ops.target);
873
	mark_target_uptodate(sh, sh->ops.target2);
874

875 876 877
	clear_bit(STRIPE_COMPUTE_RUN, &sh->state);
	if (sh->check_state == check_state_compute_run)
		sh->check_state = check_state_compute_result;
878 879 880 881
	set_bit(STRIPE_HANDLE, &sh->state);
	release_stripe(sh);
}

882 883 884 885 886 887 888 889 890
/* return a pointer to the address conversion region of the scribble buffer */
static addr_conv_t *to_addr_conv(struct stripe_head *sh,
				 struct raid5_percpu *percpu)
{
	return percpu->scribble + sizeof(struct page *) * (sh->disks + 2);
}

static struct dma_async_tx_descriptor *
ops_run_compute5(struct stripe_head *sh, struct raid5_percpu *percpu)
891 892
{
	int disks = sh->disks;
893
	struct page **xor_srcs = percpu->scribble;
894 895 896 897 898
	int target = sh->ops.target;
	struct r5dev *tgt = &sh->dev[target];
	struct page *xor_dest = tgt->page;
	int count = 0;
	struct dma_async_tx_descriptor *tx;
899
	struct async_submit_ctl submit;
900 901 902
	int i;

	pr_debug("%s: stripe %llu block: %d\n",
903
		__func__, (unsigned long long)sh->sector, target);
904 905 906 907 908 909 910 911
	BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));

	for (i = disks; i--; )
		if (i != target)
			xor_srcs[count++] = sh->dev[i].page;

	atomic_inc(&sh->count);

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Dan Williams 已提交
912
	init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST, NULL,
913
			  ops_complete_compute, sh, to_addr_conv(sh, percpu));
914
	if (unlikely(count == 1))
915
		tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, &submit);
916
	else
917
		tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
918 919 920 921

	return tx;
}

922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939
/* set_syndrome_sources - populate source buffers for gen_syndrome
 * @srcs - (struct page *) array of size sh->disks
 * @sh - stripe_head to parse
 *
 * Populates srcs in proper layout order for the stripe and returns the
 * 'count' of sources to be used in a call to async_gen_syndrome.  The P
 * destination buffer is recorded in srcs[count] and the Q destination
 * is recorded in srcs[count+1]].
 */
static int set_syndrome_sources(struct page **srcs, struct stripe_head *sh)
{
	int disks = sh->disks;
	int syndrome_disks = sh->ddf_layout ? disks : (disks - 2);
	int d0_idx = raid6_d0(sh);
	int count;
	int i;

	for (i = 0; i < disks; i++)
940
		srcs[i] = NULL;
941 942 943 944 945 946 947 948 949 950

	count = 0;
	i = d0_idx;
	do {
		int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);

		srcs[slot] = sh->dev[i].page;
		i = raid6_next_disk(i, disks);
	} while (i != d0_idx);

951
	return syndrome_disks;
952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971
}

static struct dma_async_tx_descriptor *
ops_run_compute6_1(struct stripe_head *sh, struct raid5_percpu *percpu)
{
	int disks = sh->disks;
	struct page **blocks = percpu->scribble;
	int target;
	int qd_idx = sh->qd_idx;
	struct dma_async_tx_descriptor *tx;
	struct async_submit_ctl submit;
	struct r5dev *tgt;
	struct page *dest;
	int i;
	int count;

	if (sh->ops.target < 0)
		target = sh->ops.target2;
	else if (sh->ops.target2 < 0)
		target = sh->ops.target;
972
	else
973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988
		/* we should only have one valid target */
		BUG();
	BUG_ON(target < 0);
	pr_debug("%s: stripe %llu block: %d\n",
		__func__, (unsigned long long)sh->sector, target);

	tgt = &sh->dev[target];
	BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
	dest = tgt->page;

	atomic_inc(&sh->count);

	if (target == qd_idx) {
		count = set_syndrome_sources(blocks, sh);
		blocks[count] = NULL; /* regenerating p is not necessary */
		BUG_ON(blocks[count+1] != dest); /* q should already be set */
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Dan Williams 已提交
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		init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
				  ops_complete_compute, sh,
991 992 993 994 995 996 997 998 999 1000 1001
				  to_addr_conv(sh, percpu));
		tx = async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE, &submit);
	} else {
		/* Compute any data- or p-drive using XOR */
		count = 0;
		for (i = disks; i-- ; ) {
			if (i == target || i == qd_idx)
				continue;
			blocks[count++] = sh->dev[i].page;
		}

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Dan Williams 已提交
1002 1003
		init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
				  NULL, ops_complete_compute, sh,
1004 1005 1006
				  to_addr_conv(sh, percpu));
		tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE, &submit);
	}
1007 1008 1009 1010

	return tx;
}

1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031
static struct dma_async_tx_descriptor *
ops_run_compute6_2(struct stripe_head *sh, struct raid5_percpu *percpu)
{
	int i, count, disks = sh->disks;
	int syndrome_disks = sh->ddf_layout ? disks : disks-2;
	int d0_idx = raid6_d0(sh);
	int faila = -1, failb = -1;
	int target = sh->ops.target;
	int target2 = sh->ops.target2;
	struct r5dev *tgt = &sh->dev[target];
	struct r5dev *tgt2 = &sh->dev[target2];
	struct dma_async_tx_descriptor *tx;
	struct page **blocks = percpu->scribble;
	struct async_submit_ctl submit;

	pr_debug("%s: stripe %llu block1: %d block2: %d\n",
		 __func__, (unsigned long long)sh->sector, target, target2);
	BUG_ON(target < 0 || target2 < 0);
	BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
	BUG_ON(!test_bit(R5_Wantcompute, &tgt2->flags));

1032
	/* we need to open-code set_syndrome_sources to handle the
1033 1034 1035
	 * slot number conversion for 'faila' and 'failb'
	 */
	for (i = 0; i < disks ; i++)
1036
		blocks[i] = NULL;
1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062
	count = 0;
	i = d0_idx;
	do {
		int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);

		blocks[slot] = sh->dev[i].page;

		if (i == target)
			faila = slot;
		if (i == target2)
			failb = slot;
		i = raid6_next_disk(i, disks);
	} while (i != d0_idx);

	BUG_ON(faila == failb);
	if (failb < faila)
		swap(faila, failb);
	pr_debug("%s: stripe: %llu faila: %d failb: %d\n",
		 __func__, (unsigned long long)sh->sector, faila, failb);

	atomic_inc(&sh->count);

	if (failb == syndrome_disks+1) {
		/* Q disk is one of the missing disks */
		if (faila == syndrome_disks) {
			/* Missing P+Q, just recompute */
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Dan Williams 已提交
1063 1064 1065
			init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
					  ops_complete_compute, sh,
					  to_addr_conv(sh, percpu));
1066
			return async_gen_syndrome(blocks, 0, syndrome_disks+2,
1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085
						  STRIPE_SIZE, &submit);
		} else {
			struct page *dest;
			int data_target;
			int qd_idx = sh->qd_idx;

			/* Missing D+Q: recompute D from P, then recompute Q */
			if (target == qd_idx)
				data_target = target2;
			else
				data_target = target;

			count = 0;
			for (i = disks; i-- ; ) {
				if (i == data_target || i == qd_idx)
					continue;
				blocks[count++] = sh->dev[i].page;
			}
			dest = sh->dev[data_target].page;
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Dan Williams 已提交
1086 1087 1088 1089
			init_async_submit(&submit,
					  ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
					  NULL, NULL, NULL,
					  to_addr_conv(sh, percpu));
1090 1091 1092 1093
			tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE,
				       &submit);

			count = set_syndrome_sources(blocks, sh);
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Dan Williams 已提交
1094 1095 1096
			init_async_submit(&submit, ASYNC_TX_FENCE, tx,
					  ops_complete_compute, sh,
					  to_addr_conv(sh, percpu));
1097 1098 1099 1100
			return async_gen_syndrome(blocks, 0, count+2,
						  STRIPE_SIZE, &submit);
		}
	} else {
1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114
		init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
				  ops_complete_compute, sh,
				  to_addr_conv(sh, percpu));
		if (failb == syndrome_disks) {
			/* We're missing D+P. */
			return async_raid6_datap_recov(syndrome_disks+2,
						       STRIPE_SIZE, faila,
						       blocks, &submit);
		} else {
			/* We're missing D+D. */
			return async_raid6_2data_recov(syndrome_disks+2,
						       STRIPE_SIZE, faila, failb,
						       blocks, &submit);
		}
1115 1116 1117 1118
	}
}


1119 1120 1121 1122
static void ops_complete_prexor(void *stripe_head_ref)
{
	struct stripe_head *sh = stripe_head_ref;

1123
	pr_debug("%s: stripe %llu\n", __func__,
1124 1125 1126 1127
		(unsigned long long)sh->sector);
}

static struct dma_async_tx_descriptor *
1128 1129
ops_run_prexor(struct stripe_head *sh, struct raid5_percpu *percpu,
	       struct dma_async_tx_descriptor *tx)
1130 1131
{
	int disks = sh->disks;
1132
	struct page **xor_srcs = percpu->scribble;
1133
	int count = 0, pd_idx = sh->pd_idx, i;
1134
	struct async_submit_ctl submit;
1135 1136 1137 1138

	/* existing parity data subtracted */
	struct page *xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;

1139
	pr_debug("%s: stripe %llu\n", __func__,
1140 1141 1142 1143 1144
		(unsigned long long)sh->sector);

	for (i = disks; i--; ) {
		struct r5dev *dev = &sh->dev[i];
		/* Only process blocks that are known to be uptodate */
1145
		if (test_bit(R5_Wantdrain, &dev->flags))
1146 1147 1148
			xor_srcs[count++] = dev->page;
	}

D
Dan Williams 已提交
1149
	init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
1150
			  ops_complete_prexor, sh, to_addr_conv(sh, percpu));
1151
	tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
1152 1153 1154 1155 1156

	return tx;
}

static struct dma_async_tx_descriptor *
1157
ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
1158 1159
{
	int disks = sh->disks;
1160
	int i;
1161

1162
	pr_debug("%s: stripe %llu\n", __func__,
1163 1164 1165 1166 1167 1168
		(unsigned long long)sh->sector);

	for (i = disks; i--; ) {
		struct r5dev *dev = &sh->dev[i];
		struct bio *chosen;

1169
		if (test_and_clear_bit(R5_Wantdrain, &dev->flags)) {
1170 1171
			struct bio *wbi;

S
Shaohua Li 已提交
1172
			spin_lock_irq(&sh->stripe_lock);
1173 1174 1175 1176
			chosen = dev->towrite;
			dev->towrite = NULL;
			BUG_ON(dev->written);
			wbi = dev->written = chosen;
S
Shaohua Li 已提交
1177
			spin_unlock_irq(&sh->stripe_lock);
1178 1179 1180

			while (wbi && wbi->bi_sector <
				dev->sector + STRIPE_SECTORS) {
T
Tejun Heo 已提交
1181 1182
				if (wbi->bi_rw & REQ_FUA)
					set_bit(R5_WantFUA, &dev->flags);
S
Shaohua Li 已提交
1183 1184
				if (wbi->bi_rw & REQ_SYNC)
					set_bit(R5_SyncIO, &dev->flags);
1185
				if (wbi->bi_rw & REQ_DISCARD)
S
Shaohua Li 已提交
1186
					set_bit(R5_Discard, &dev->flags);
1187
				else
S
Shaohua Li 已提交
1188 1189
					tx = async_copy_data(1, wbi, dev->page,
						dev->sector, tx);
1190 1191 1192 1193 1194 1195 1196 1197
				wbi = r5_next_bio(wbi, dev->sector);
			}
		}
	}

	return tx;
}

1198
static void ops_complete_reconstruct(void *stripe_head_ref)
1199 1200
{
	struct stripe_head *sh = stripe_head_ref;
1201 1202 1203 1204
	int disks = sh->disks;
	int pd_idx = sh->pd_idx;
	int qd_idx = sh->qd_idx;
	int i;
1205
	bool fua = false, sync = false, discard = false;
1206

1207
	pr_debug("%s: stripe %llu\n", __func__,
1208 1209
		(unsigned long long)sh->sector);

S
Shaohua Li 已提交
1210
	for (i = disks; i--; ) {
T
Tejun Heo 已提交
1211
		fua |= test_bit(R5_WantFUA, &sh->dev[i].flags);
S
Shaohua Li 已提交
1212
		sync |= test_bit(R5_SyncIO, &sh->dev[i].flags);
1213
		discard |= test_bit(R5_Discard, &sh->dev[i].flags);
S
Shaohua Li 已提交
1214
	}
T
Tejun Heo 已提交
1215

1216 1217
	for (i = disks; i--; ) {
		struct r5dev *dev = &sh->dev[i];
1218

T
Tejun Heo 已提交
1219
		if (dev->written || i == pd_idx || i == qd_idx) {
1220 1221
			if (!discard)
				set_bit(R5_UPTODATE, &dev->flags);
T
Tejun Heo 已提交
1222 1223
			if (fua)
				set_bit(R5_WantFUA, &dev->flags);
S
Shaohua Li 已提交
1224 1225
			if (sync)
				set_bit(R5_SyncIO, &dev->flags);
T
Tejun Heo 已提交
1226
		}
1227 1228
	}

1229 1230 1231 1232 1233 1234 1235 1236
	if (sh->reconstruct_state == reconstruct_state_drain_run)
		sh->reconstruct_state = reconstruct_state_drain_result;
	else if (sh->reconstruct_state == reconstruct_state_prexor_drain_run)
		sh->reconstruct_state = reconstruct_state_prexor_drain_result;
	else {
		BUG_ON(sh->reconstruct_state != reconstruct_state_run);
		sh->reconstruct_state = reconstruct_state_result;
	}
1237 1238 1239 1240 1241 1242

	set_bit(STRIPE_HANDLE, &sh->state);
	release_stripe(sh);
}

static void
1243 1244
ops_run_reconstruct5(struct stripe_head *sh, struct raid5_percpu *percpu,
		     struct dma_async_tx_descriptor *tx)
1245 1246
{
	int disks = sh->disks;
1247
	struct page **xor_srcs = percpu->scribble;
1248
	struct async_submit_ctl submit;
1249 1250
	int count = 0, pd_idx = sh->pd_idx, i;
	struct page *xor_dest;
1251
	int prexor = 0;
1252 1253
	unsigned long flags;

1254
	pr_debug("%s: stripe %llu\n", __func__,
1255 1256
		(unsigned long long)sh->sector);

S
Shaohua Li 已提交
1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268
	for (i = 0; i < sh->disks; i++) {
		if (pd_idx == i)
			continue;
		if (!test_bit(R5_Discard, &sh->dev[i].flags))
			break;
	}
	if (i >= sh->disks) {
		atomic_inc(&sh->count);
		set_bit(R5_Discard, &sh->dev[pd_idx].flags);
		ops_complete_reconstruct(sh);
		return;
	}
1269 1270 1271
	/* check if prexor is active which means only process blocks
	 * that are part of a read-modify-write (written)
	 */
1272 1273
	if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
		prexor = 1;
1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293
		xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
		for (i = disks; i--; ) {
			struct r5dev *dev = &sh->dev[i];
			if (dev->written)
				xor_srcs[count++] = dev->page;
		}
	} else {
		xor_dest = sh->dev[pd_idx].page;
		for (i = disks; i--; ) {
			struct r5dev *dev = &sh->dev[i];
			if (i != pd_idx)
				xor_srcs[count++] = dev->page;
		}
	}

	/* 1/ if we prexor'd then the dest is reused as a source
	 * 2/ if we did not prexor then we are redoing the parity
	 * set ASYNC_TX_XOR_DROP_DST and ASYNC_TX_XOR_ZERO_DST
	 * for the synchronous xor case
	 */
1294
	flags = ASYNC_TX_ACK |
1295 1296 1297 1298
		(prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST);

	atomic_inc(&sh->count);

1299
	init_async_submit(&submit, flags, tx, ops_complete_reconstruct, sh,
1300
			  to_addr_conv(sh, percpu));
1301 1302 1303 1304
	if (unlikely(count == 1))
		tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, &submit);
	else
		tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
1305 1306
}

1307 1308 1309 1310 1311 1312
static void
ops_run_reconstruct6(struct stripe_head *sh, struct raid5_percpu *percpu,
		     struct dma_async_tx_descriptor *tx)
{
	struct async_submit_ctl submit;
	struct page **blocks = percpu->scribble;
S
Shaohua Li 已提交
1313
	int count, i;
1314 1315 1316

	pr_debug("%s: stripe %llu\n", __func__, (unsigned long long)sh->sector);

S
Shaohua Li 已提交
1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330
	for (i = 0; i < sh->disks; i++) {
		if (sh->pd_idx == i || sh->qd_idx == i)
			continue;
		if (!test_bit(R5_Discard, &sh->dev[i].flags))
			break;
	}
	if (i >= sh->disks) {
		atomic_inc(&sh->count);
		set_bit(R5_Discard, &sh->dev[sh->pd_idx].flags);
		set_bit(R5_Discard, &sh->dev[sh->qd_idx].flags);
		ops_complete_reconstruct(sh);
		return;
	}

1331 1332 1333 1334 1335 1336 1337
	count = set_syndrome_sources(blocks, sh);

	atomic_inc(&sh->count);

	init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_reconstruct,
			  sh, to_addr_conv(sh, percpu));
	async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE,  &submit);
1338 1339 1340 1341 1342 1343
}

static void ops_complete_check(void *stripe_head_ref)
{
	struct stripe_head *sh = stripe_head_ref;

1344
	pr_debug("%s: stripe %llu\n", __func__,
1345 1346
		(unsigned long long)sh->sector);

1347
	sh->check_state = check_state_check_result;
1348 1349 1350 1351
	set_bit(STRIPE_HANDLE, &sh->state);
	release_stripe(sh);
}

1352
static void ops_run_check_p(struct stripe_head *sh, struct raid5_percpu *percpu)
1353 1354
{
	int disks = sh->disks;
1355 1356 1357
	int pd_idx = sh->pd_idx;
	int qd_idx = sh->qd_idx;
	struct page *xor_dest;
1358
	struct page **xor_srcs = percpu->scribble;
1359
	struct dma_async_tx_descriptor *tx;
1360
	struct async_submit_ctl submit;
1361 1362
	int count;
	int i;
1363

1364
	pr_debug("%s: stripe %llu\n", __func__,
1365 1366
		(unsigned long long)sh->sector);

1367 1368 1369
	count = 0;
	xor_dest = sh->dev[pd_idx].page;
	xor_srcs[count++] = xor_dest;
1370
	for (i = disks; i--; ) {
1371 1372 1373
		if (i == pd_idx || i == qd_idx)
			continue;
		xor_srcs[count++] = sh->dev[i].page;
1374 1375
	}

1376 1377
	init_async_submit(&submit, 0, NULL, NULL, NULL,
			  to_addr_conv(sh, percpu));
D
Dan Williams 已提交
1378
	tx = async_xor_val(xor_dest, xor_srcs, 0, count, STRIPE_SIZE,
1379
			   &sh->ops.zero_sum_result, &submit);
1380 1381

	atomic_inc(&sh->count);
1382 1383
	init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_check, sh, NULL);
	tx = async_trigger_callback(&submit);
1384 1385
}

1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397
static void ops_run_check_pq(struct stripe_head *sh, struct raid5_percpu *percpu, int checkp)
{
	struct page **srcs = percpu->scribble;
	struct async_submit_ctl submit;
	int count;

	pr_debug("%s: stripe %llu checkp: %d\n", __func__,
		(unsigned long long)sh->sector, checkp);

	count = set_syndrome_sources(srcs, sh);
	if (!checkp)
		srcs[count] = NULL;
1398 1399

	atomic_inc(&sh->count);
1400 1401 1402 1403
	init_async_submit(&submit, ASYNC_TX_ACK, NULL, ops_complete_check,
			  sh, to_addr_conv(sh, percpu));
	async_syndrome_val(srcs, 0, count+2, STRIPE_SIZE,
			   &sh->ops.zero_sum_result, percpu->spare_page, &submit);
1404 1405
}

N
NeilBrown 已提交
1406
static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request)
1407 1408 1409
{
	int overlap_clear = 0, i, disks = sh->disks;
	struct dma_async_tx_descriptor *tx = NULL;
1410
	struct r5conf *conf = sh->raid_conf;
1411
	int level = conf->level;
1412 1413
	struct raid5_percpu *percpu;
	unsigned long cpu;
1414

1415 1416
	cpu = get_cpu();
	percpu = per_cpu_ptr(conf->percpu, cpu);
1417
	if (test_bit(STRIPE_OP_BIOFILL, &ops_request)) {
1418 1419 1420 1421
		ops_run_biofill(sh);
		overlap_clear++;
	}

1422
	if (test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request)) {
1423 1424 1425 1426 1427 1428 1429 1430 1431 1432
		if (level < 6)
			tx = ops_run_compute5(sh, percpu);
		else {
			if (sh->ops.target2 < 0 || sh->ops.target < 0)
				tx = ops_run_compute6_1(sh, percpu);
			else
				tx = ops_run_compute6_2(sh, percpu);
		}
		/* terminate the chain if reconstruct is not set to be run */
		if (tx && !test_bit(STRIPE_OP_RECONSTRUCT, &ops_request))
1433 1434
			async_tx_ack(tx);
	}
1435

1436
	if (test_bit(STRIPE_OP_PREXOR, &ops_request))
1437
		tx = ops_run_prexor(sh, percpu, tx);
1438

1439
	if (test_bit(STRIPE_OP_BIODRAIN, &ops_request)) {
1440
		tx = ops_run_biodrain(sh, tx);
1441 1442 1443
		overlap_clear++;
	}

1444 1445 1446 1447 1448 1449
	if (test_bit(STRIPE_OP_RECONSTRUCT, &ops_request)) {
		if (level < 6)
			ops_run_reconstruct5(sh, percpu, tx);
		else
			ops_run_reconstruct6(sh, percpu, tx);
	}
1450

1451 1452 1453 1454 1455 1456 1457 1458 1459 1460
	if (test_bit(STRIPE_OP_CHECK, &ops_request)) {
		if (sh->check_state == check_state_run)
			ops_run_check_p(sh, percpu);
		else if (sh->check_state == check_state_run_q)
			ops_run_check_pq(sh, percpu, 0);
		else if (sh->check_state == check_state_run_pq)
			ops_run_check_pq(sh, percpu, 1);
		else
			BUG();
	}
1461 1462 1463 1464 1465 1466 1467

	if (overlap_clear)
		for (i = disks; i--; ) {
			struct r5dev *dev = &sh->dev[i];
			if (test_and_clear_bit(R5_Overlap, &dev->flags))
				wake_up(&sh->raid_conf->wait_for_overlap);
		}
1468
	put_cpu();
1469 1470
}

1471
static int grow_one_stripe(struct r5conf *conf)
L
Linus Torvalds 已提交
1472 1473
{
	struct stripe_head *sh;
N
Namhyung Kim 已提交
1474
	sh = kmem_cache_zalloc(conf->slab_cache, GFP_KERNEL);
1475 1476
	if (!sh)
		return 0;
N
Namhyung Kim 已提交
1477

1478 1479
	sh->raid_conf = conf;

S
Shaohua Li 已提交
1480 1481
	spin_lock_init(&sh->stripe_lock);

1482 1483
	if (grow_buffers(sh)) {
		shrink_buffers(sh);
1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494
		kmem_cache_free(conf->slab_cache, sh);
		return 0;
	}
	/* we just created an active stripe so... */
	atomic_set(&sh->count, 1);
	atomic_inc(&conf->active_stripes);
	INIT_LIST_HEAD(&sh->lru);
	release_stripe(sh);
	return 1;
}

1495
static int grow_stripes(struct r5conf *conf, int num)
1496
{
1497
	struct kmem_cache *sc;
1498
	int devs = max(conf->raid_disks, conf->previous_raid_disks);
L
Linus Torvalds 已提交
1499

1500 1501 1502 1503 1504 1505 1506 1507
	if (conf->mddev->gendisk)
		sprintf(conf->cache_name[0],
			"raid%d-%s", conf->level, mdname(conf->mddev));
	else
		sprintf(conf->cache_name[0],
			"raid%d-%p", conf->level, conf->mddev);
	sprintf(conf->cache_name[1], "%s-alt", conf->cache_name[0]);

1508 1509
	conf->active_name = 0;
	sc = kmem_cache_create(conf->cache_name[conf->active_name],
L
Linus Torvalds 已提交
1510
			       sizeof(struct stripe_head)+(devs-1)*sizeof(struct r5dev),
1511
			       0, 0, NULL);
L
Linus Torvalds 已提交
1512 1513 1514
	if (!sc)
		return 1;
	conf->slab_cache = sc;
1515
	conf->pool_size = devs;
1516
	while (num--)
1517
		if (!grow_one_stripe(conf))
L
Linus Torvalds 已提交
1518 1519 1520
			return 1;
	return 0;
}
1521

1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543
/**
 * scribble_len - return the required size of the scribble region
 * @num - total number of disks in the array
 *
 * The size must be enough to contain:
 * 1/ a struct page pointer for each device in the array +2
 * 2/ room to convert each entry in (1) to its corresponding dma
 *    (dma_map_page()) or page (page_address()) address.
 *
 * Note: the +2 is for the destination buffers of the ddf/raid6 case where we
 * calculate over all devices (not just the data blocks), using zeros in place
 * of the P and Q blocks.
 */
static size_t scribble_len(int num)
{
	size_t len;

	len = sizeof(struct page *) * (num+2) + sizeof(addr_conv_t) * (num+2);

	return len;
}

1544
static int resize_stripes(struct r5conf *conf, int newsize)
1545 1546 1547 1548 1549 1550 1551
{
	/* Make all the stripes able to hold 'newsize' devices.
	 * New slots in each stripe get 'page' set to a new page.
	 *
	 * This happens in stages:
	 * 1/ create a new kmem_cache and allocate the required number of
	 *    stripe_heads.
M
Masanari Iida 已提交
1552
	 * 2/ gather all the old stripe_heads and transfer the pages across
1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571
	 *    to the new stripe_heads.  This will have the side effect of
	 *    freezing the array as once all stripe_heads have been collected,
	 *    no IO will be possible.  Old stripe heads are freed once their
	 *    pages have been transferred over, and the old kmem_cache is
	 *    freed when all stripes are done.
	 * 3/ reallocate conf->disks to be suitable bigger.  If this fails,
	 *    we simple return a failre status - no need to clean anything up.
	 * 4/ allocate new pages for the new slots in the new stripe_heads.
	 *    If this fails, we don't bother trying the shrink the
	 *    stripe_heads down again, we just leave them as they are.
	 *    As each stripe_head is processed the new one is released into
	 *    active service.
	 *
	 * Once step2 is started, we cannot afford to wait for a write,
	 * so we use GFP_NOIO allocations.
	 */
	struct stripe_head *osh, *nsh;
	LIST_HEAD(newstripes);
	struct disk_info *ndisks;
1572
	unsigned long cpu;
1573
	int err;
1574
	struct kmem_cache *sc;
1575 1576 1577 1578 1579
	int i;

	if (newsize <= conf->pool_size)
		return 0; /* never bother to shrink */

1580 1581 1582
	err = md_allow_write(conf->mddev);
	if (err)
		return err;
1583

1584 1585 1586
	/* Step 1 */
	sc = kmem_cache_create(conf->cache_name[1-conf->active_name],
			       sizeof(struct stripe_head)+(newsize-1)*sizeof(struct r5dev),
1587
			       0, 0, NULL);
1588 1589 1590 1591
	if (!sc)
		return -ENOMEM;

	for (i = conf->max_nr_stripes; i; i--) {
N
Namhyung Kim 已提交
1592
		nsh = kmem_cache_zalloc(sc, GFP_KERNEL);
1593 1594 1595 1596
		if (!nsh)
			break;

		nsh->raid_conf = conf;
1597
		spin_lock_init(&nsh->stripe_lock);
1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618

		list_add(&nsh->lru, &newstripes);
	}
	if (i) {
		/* didn't get enough, give up */
		while (!list_empty(&newstripes)) {
			nsh = list_entry(newstripes.next, struct stripe_head, lru);
			list_del(&nsh->lru);
			kmem_cache_free(sc, nsh);
		}
		kmem_cache_destroy(sc);
		return -ENOMEM;
	}
	/* Step 2 - Must use GFP_NOIO now.
	 * OK, we have enough stripes, start collecting inactive
	 * stripes and copying them over
	 */
	list_for_each_entry(nsh, &newstripes, lru) {
		spin_lock_irq(&conf->device_lock);
		wait_event_lock_irq(conf->wait_for_stripe,
				    !list_empty(&conf->inactive_list),
1619
				    conf->device_lock);
1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633
		osh = get_free_stripe(conf);
		spin_unlock_irq(&conf->device_lock);
		atomic_set(&nsh->count, 1);
		for(i=0; i<conf->pool_size; i++)
			nsh->dev[i].page = osh->dev[i].page;
		for( ; i<newsize; i++)
			nsh->dev[i].page = NULL;
		kmem_cache_free(conf->slab_cache, osh);
	}
	kmem_cache_destroy(conf->slab_cache);

	/* Step 3.
	 * At this point, we are holding all the stripes so the array
	 * is completely stalled, so now is a good time to resize
1634
	 * conf->disks and the scribble region
1635 1636 1637 1638 1639 1640 1641 1642 1643 1644
	 */
	ndisks = kzalloc(newsize * sizeof(struct disk_info), GFP_NOIO);
	if (ndisks) {
		for (i=0; i<conf->raid_disks; i++)
			ndisks[i] = conf->disks[i];
		kfree(conf->disks);
		conf->disks = ndisks;
	} else
		err = -ENOMEM;

1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663
	get_online_cpus();
	conf->scribble_len = scribble_len(newsize);
	for_each_present_cpu(cpu) {
		struct raid5_percpu *percpu;
		void *scribble;

		percpu = per_cpu_ptr(conf->percpu, cpu);
		scribble = kmalloc(conf->scribble_len, GFP_NOIO);

		if (scribble) {
			kfree(percpu->scribble);
			percpu->scribble = scribble;
		} else {
			err = -ENOMEM;
			break;
		}
	}
	put_online_cpus();

1664 1665 1666 1667
	/* Step 4, return new stripes to service */
	while(!list_empty(&newstripes)) {
		nsh = list_entry(newstripes.next, struct stripe_head, lru);
		list_del_init(&nsh->lru);
1668

1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684
		for (i=conf->raid_disks; i < newsize; i++)
			if (nsh->dev[i].page == NULL) {
				struct page *p = alloc_page(GFP_NOIO);
				nsh->dev[i].page = p;
				if (!p)
					err = -ENOMEM;
			}
		release_stripe(nsh);
	}
	/* critical section pass, GFP_NOIO no longer needed */

	conf->slab_cache = sc;
	conf->active_name = 1-conf->active_name;
	conf->pool_size = newsize;
	return err;
}
L
Linus Torvalds 已提交
1685

1686
static int drop_one_stripe(struct r5conf *conf)
L
Linus Torvalds 已提交
1687 1688 1689
{
	struct stripe_head *sh;

1690 1691 1692 1693 1694
	spin_lock_irq(&conf->device_lock);
	sh = get_free_stripe(conf);
	spin_unlock_irq(&conf->device_lock);
	if (!sh)
		return 0;
1695
	BUG_ON(atomic_read(&sh->count));
1696
	shrink_buffers(sh);
1697 1698 1699 1700 1701
	kmem_cache_free(conf->slab_cache, sh);
	atomic_dec(&conf->active_stripes);
	return 1;
}

1702
static void shrink_stripes(struct r5conf *conf)
1703 1704 1705 1706
{
	while (drop_one_stripe(conf))
		;

N
NeilBrown 已提交
1707 1708
	if (conf->slab_cache)
		kmem_cache_destroy(conf->slab_cache);
L
Linus Torvalds 已提交
1709 1710 1711
	conf->slab_cache = NULL;
}

1712
static void raid5_end_read_request(struct bio * bi, int error)
L
Linus Torvalds 已提交
1713
{
1714
	struct stripe_head *sh = bi->bi_private;
1715
	struct r5conf *conf = sh->raid_conf;
1716
	int disks = sh->disks, i;
L
Linus Torvalds 已提交
1717
	int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
1718
	char b[BDEVNAME_SIZE];
1719
	struct md_rdev *rdev = NULL;
1720
	sector_t s;
L
Linus Torvalds 已提交
1721 1722 1723 1724 1725

	for (i=0 ; i<disks; i++)
		if (bi == &sh->dev[i].req)
			break;

1726 1727
	pr_debug("end_read_request %llu/%d, count: %d, uptodate %d.\n",
		(unsigned long long)sh->sector, i, atomic_read(&sh->count),
L
Linus Torvalds 已提交
1728 1729 1730
		uptodate);
	if (i == disks) {
		BUG();
1731
		return;
L
Linus Torvalds 已提交
1732
	}
1733
	if (test_bit(R5_ReadRepl, &sh->dev[i].flags))
1734 1735 1736 1737 1738
		/* If replacement finished while this request was outstanding,
		 * 'replacement' might be NULL already.
		 * In that case it moved down to 'rdev'.
		 * rdev is not removed until all requests are finished.
		 */
1739
		rdev = conf->disks[i].replacement;
1740
	if (!rdev)
1741
		rdev = conf->disks[i].rdev;
L
Linus Torvalds 已提交
1742

1743 1744 1745 1746
	if (use_new_offset(conf, sh))
		s = sh->sector + rdev->new_data_offset;
	else
		s = sh->sector + rdev->data_offset;
L
Linus Torvalds 已提交
1747 1748
	if (uptodate) {
		set_bit(R5_UPTODATE, &sh->dev[i].flags);
1749
		if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
1750 1751 1752 1753
			/* Note that this cannot happen on a
			 * replacement device.  We just fail those on
			 * any error
			 */
1754 1755 1756 1757 1758
			printk_ratelimited(
				KERN_INFO
				"md/raid:%s: read error corrected"
				" (%lu sectors at %llu on %s)\n",
				mdname(conf->mddev), STRIPE_SECTORS,
1759
				(unsigned long long)s,
1760
				bdevname(rdev->bdev, b));
1761
			atomic_add(STRIPE_SECTORS, &rdev->corrected_errors);
1762 1763
			clear_bit(R5_ReadError, &sh->dev[i].flags);
			clear_bit(R5_ReWrite, &sh->dev[i].flags);
1764 1765 1766
		} else if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
			clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);

1767 1768
		if (atomic_read(&rdev->read_errors))
			atomic_set(&rdev->read_errors, 0);
L
Linus Torvalds 已提交
1769
	} else {
1770
		const char *bdn = bdevname(rdev->bdev, b);
1771
		int retry = 0;
1772
		int set_bad = 0;
1773

L
Linus Torvalds 已提交
1774
		clear_bit(R5_UPTODATE, &sh->dev[i].flags);
1775
		atomic_inc(&rdev->read_errors);
1776 1777 1778 1779 1780 1781
		if (test_bit(R5_ReadRepl, &sh->dev[i].flags))
			printk_ratelimited(
				KERN_WARNING
				"md/raid:%s: read error on replacement device "
				"(sector %llu on %s).\n",
				mdname(conf->mddev),
1782
				(unsigned long long)s,
1783
				bdn);
1784 1785
		else if (conf->mddev->degraded >= conf->max_degraded) {
			set_bad = 1;
1786 1787 1788 1789 1790
			printk_ratelimited(
				KERN_WARNING
				"md/raid:%s: read error not correctable "
				"(sector %llu on %s).\n",
				mdname(conf->mddev),
1791
				(unsigned long long)s,
1792
				bdn);
1793
		} else if (test_bit(R5_ReWrite, &sh->dev[i].flags)) {
1794
			/* Oh, no!!! */
1795
			set_bad = 1;
1796 1797 1798 1799 1800
			printk_ratelimited(
				KERN_WARNING
				"md/raid:%s: read error NOT corrected!! "
				"(sector %llu on %s).\n",
				mdname(conf->mddev),
1801
				(unsigned long long)s,
1802
				bdn);
1803
		} else if (atomic_read(&rdev->read_errors)
1804
			 > conf->max_nr_stripes)
N
NeilBrown 已提交
1805
			printk(KERN_WARNING
1806
			       "md/raid:%s: Too many read errors, failing device %s.\n",
1807
			       mdname(conf->mddev), bdn);
1808 1809 1810
		else
			retry = 1;
		if (retry)
1811 1812 1813 1814 1815
			if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags)) {
				set_bit(R5_ReadError, &sh->dev[i].flags);
				clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);
			} else
				set_bit(R5_ReadNoMerge, &sh->dev[i].flags);
1816
		else {
1817 1818
			clear_bit(R5_ReadError, &sh->dev[i].flags);
			clear_bit(R5_ReWrite, &sh->dev[i].flags);
1819 1820 1821 1822 1823
			if (!(set_bad
			      && test_bit(In_sync, &rdev->flags)
			      && rdev_set_badblocks(
				      rdev, sh->sector, STRIPE_SECTORS, 0)))
				md_error(conf->mddev, rdev);
1824
		}
L
Linus Torvalds 已提交
1825
	}
1826
	rdev_dec_pending(rdev, conf->mddev);
L
Linus Torvalds 已提交
1827 1828 1829 1830 1831
	clear_bit(R5_LOCKED, &sh->dev[i].flags);
	set_bit(STRIPE_HANDLE, &sh->state);
	release_stripe(sh);
}

1832
static void raid5_end_write_request(struct bio *bi, int error)
L
Linus Torvalds 已提交
1833
{
1834
	struct stripe_head *sh = bi->bi_private;
1835
	struct r5conf *conf = sh->raid_conf;
1836
	int disks = sh->disks, i;
1837
	struct md_rdev *uninitialized_var(rdev);
L
Linus Torvalds 已提交
1838
	int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
1839 1840
	sector_t first_bad;
	int bad_sectors;
1841
	int replacement = 0;
L
Linus Torvalds 已提交
1842

1843 1844 1845
	for (i = 0 ; i < disks; i++) {
		if (bi == &sh->dev[i].req) {
			rdev = conf->disks[i].rdev;
L
Linus Torvalds 已提交
1846
			break;
1847 1848 1849
		}
		if (bi == &sh->dev[i].rreq) {
			rdev = conf->disks[i].replacement;
1850 1851 1852 1853 1854 1855 1856 1857
			if (rdev)
				replacement = 1;
			else
				/* rdev was removed and 'replacement'
				 * replaced it.  rdev is not removed
				 * until all requests are finished.
				 */
				rdev = conf->disks[i].rdev;
1858 1859 1860
			break;
		}
	}
1861
	pr_debug("end_write_request %llu/%d, count %d, uptodate: %d.\n",
L
Linus Torvalds 已提交
1862 1863 1864 1865
		(unsigned long long)sh->sector, i, atomic_read(&sh->count),
		uptodate);
	if (i == disks) {
		BUG();
1866
		return;
L
Linus Torvalds 已提交
1867 1868
	}

1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879
	if (replacement) {
		if (!uptodate)
			md_error(conf->mddev, rdev);
		else if (is_badblock(rdev, sh->sector,
				     STRIPE_SECTORS,
				     &first_bad, &bad_sectors))
			set_bit(R5_MadeGoodRepl, &sh->dev[i].flags);
	} else {
		if (!uptodate) {
			set_bit(WriteErrorSeen, &rdev->flags);
			set_bit(R5_WriteError, &sh->dev[i].flags);
1880 1881 1882
			if (!test_and_set_bit(WantReplacement, &rdev->flags))
				set_bit(MD_RECOVERY_NEEDED,
					&rdev->mddev->recovery);
1883 1884 1885 1886 1887 1888
		} else if (is_badblock(rdev, sh->sector,
				       STRIPE_SECTORS,
				       &first_bad, &bad_sectors))
			set_bit(R5_MadeGood, &sh->dev[i].flags);
	}
	rdev_dec_pending(rdev, conf->mddev);
L
Linus Torvalds 已提交
1889

1890 1891
	if (!test_and_clear_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags))
		clear_bit(R5_LOCKED, &sh->dev[i].flags);
L
Linus Torvalds 已提交
1892
	set_bit(STRIPE_HANDLE, &sh->state);
1893
	release_stripe(sh);
L
Linus Torvalds 已提交
1894 1895
}

1896
static sector_t compute_blocknr(struct stripe_head *sh, int i, int previous);
L
Linus Torvalds 已提交
1897
	
1898
static void raid5_build_block(struct stripe_head *sh, int i, int previous)
L
Linus Torvalds 已提交
1899 1900 1901 1902 1903 1904 1905 1906
{
	struct r5dev *dev = &sh->dev[i];

	bio_init(&dev->req);
	dev->req.bi_io_vec = &dev->vec;
	dev->req.bi_vcnt++;
	dev->req.bi_max_vecs++;
	dev->req.bi_private = sh;
1907
	dev->vec.bv_page = dev->page;
L
Linus Torvalds 已提交
1908

1909 1910 1911 1912 1913 1914 1915
	bio_init(&dev->rreq);
	dev->rreq.bi_io_vec = &dev->rvec;
	dev->rreq.bi_vcnt++;
	dev->rreq.bi_max_vecs++;
	dev->rreq.bi_private = sh;
	dev->rvec.bv_page = dev->page;

L
Linus Torvalds 已提交
1916
	dev->flags = 0;
1917
	dev->sector = compute_blocknr(sh, i, previous);
L
Linus Torvalds 已提交
1918 1919
}

1920
static void error(struct mddev *mddev, struct md_rdev *rdev)
L
Linus Torvalds 已提交
1921 1922
{
	char b[BDEVNAME_SIZE];
1923
	struct r5conf *conf = mddev->private;
1924
	unsigned long flags;
1925
	pr_debug("raid456: error called\n");
L
Linus Torvalds 已提交
1926

1927 1928 1929 1930 1931 1932
	spin_lock_irqsave(&conf->device_lock, flags);
	clear_bit(In_sync, &rdev->flags);
	mddev->degraded = calc_degraded(conf);
	spin_unlock_irqrestore(&conf->device_lock, flags);
	set_bit(MD_RECOVERY_INTR, &mddev->recovery);

1933
	set_bit(Blocked, &rdev->flags);
1934 1935 1936 1937 1938 1939 1940 1941 1942
	set_bit(Faulty, &rdev->flags);
	set_bit(MD_CHANGE_DEVS, &mddev->flags);
	printk(KERN_ALERT
	       "md/raid:%s: Disk failure on %s, disabling device.\n"
	       "md/raid:%s: Operation continuing on %d devices.\n",
	       mdname(mddev),
	       bdevname(rdev->bdev, b),
	       mdname(mddev),
	       conf->raid_disks - mddev->degraded);
1943
}
L
Linus Torvalds 已提交
1944 1945 1946 1947 1948

/*
 * Input: a 'big' sector number,
 * Output: index of the data and parity disk, and the sector # in them.
 */
1949
static sector_t raid5_compute_sector(struct r5conf *conf, sector_t r_sector,
1950 1951
				     int previous, int *dd_idx,
				     struct stripe_head *sh)
L
Linus Torvalds 已提交
1952
{
N
NeilBrown 已提交
1953
	sector_t stripe, stripe2;
1954
	sector_t chunk_number;
L
Linus Torvalds 已提交
1955
	unsigned int chunk_offset;
1956
	int pd_idx, qd_idx;
1957
	int ddf_layout = 0;
L
Linus Torvalds 已提交
1958
	sector_t new_sector;
1959 1960
	int algorithm = previous ? conf->prev_algo
				 : conf->algorithm;
1961 1962
	int sectors_per_chunk = previous ? conf->prev_chunk_sectors
					 : conf->chunk_sectors;
1963 1964 1965
	int raid_disks = previous ? conf->previous_raid_disks
				  : conf->raid_disks;
	int data_disks = raid_disks - conf->max_degraded;
L
Linus Torvalds 已提交
1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977

	/* First compute the information on this sector */

	/*
	 * Compute the chunk number and the sector offset inside the chunk
	 */
	chunk_offset = sector_div(r_sector, sectors_per_chunk);
	chunk_number = r_sector;

	/*
	 * Compute the stripe number
	 */
1978 1979
	stripe = chunk_number;
	*dd_idx = sector_div(stripe, data_disks);
N
NeilBrown 已提交
1980
	stripe2 = stripe;
L
Linus Torvalds 已提交
1981 1982 1983
	/*
	 * Select the parity disk based on the user selected algorithm.
	 */
1984
	pd_idx = qd_idx = -1;
1985 1986
	switch(conf->level) {
	case 4:
1987
		pd_idx = data_disks;
1988 1989
		break;
	case 5:
1990
		switch (algorithm) {
L
Linus Torvalds 已提交
1991
		case ALGORITHM_LEFT_ASYMMETRIC:
N
NeilBrown 已提交
1992
			pd_idx = data_disks - sector_div(stripe2, raid_disks);
1993
			if (*dd_idx >= pd_idx)
L
Linus Torvalds 已提交
1994 1995 1996
				(*dd_idx)++;
			break;
		case ALGORITHM_RIGHT_ASYMMETRIC:
N
NeilBrown 已提交
1997
			pd_idx = sector_div(stripe2, raid_disks);
1998
			if (*dd_idx >= pd_idx)
L
Linus Torvalds 已提交
1999 2000 2001
				(*dd_idx)++;
			break;
		case ALGORITHM_LEFT_SYMMETRIC:
N
NeilBrown 已提交
2002
			pd_idx = data_disks - sector_div(stripe2, raid_disks);
2003
			*dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
L
Linus Torvalds 已提交
2004 2005
			break;
		case ALGORITHM_RIGHT_SYMMETRIC:
N
NeilBrown 已提交
2006
			pd_idx = sector_div(stripe2, raid_disks);
2007
			*dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
L
Linus Torvalds 已提交
2008
			break;
2009 2010 2011 2012 2013 2014 2015
		case ALGORITHM_PARITY_0:
			pd_idx = 0;
			(*dd_idx)++;
			break;
		case ALGORITHM_PARITY_N:
			pd_idx = data_disks;
			break;
L
Linus Torvalds 已提交
2016
		default:
2017
			BUG();
2018 2019 2020 2021
		}
		break;
	case 6:

2022
		switch (algorithm) {
2023
		case ALGORITHM_LEFT_ASYMMETRIC:
N
NeilBrown 已提交
2024
			pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2025 2026
			qd_idx = pd_idx + 1;
			if (pd_idx == raid_disks-1) {
2027
				(*dd_idx)++;	/* Q D D D P */
2028 2029
				qd_idx = 0;
			} else if (*dd_idx >= pd_idx)
2030 2031 2032
				(*dd_idx) += 2; /* D D P Q D */
			break;
		case ALGORITHM_RIGHT_ASYMMETRIC:
N
NeilBrown 已提交
2033
			pd_idx = sector_div(stripe2, raid_disks);
2034 2035
			qd_idx = pd_idx + 1;
			if (pd_idx == raid_disks-1) {
2036
				(*dd_idx)++;	/* Q D D D P */
2037 2038
				qd_idx = 0;
			} else if (*dd_idx >= pd_idx)
2039 2040 2041
				(*dd_idx) += 2; /* D D P Q D */
			break;
		case ALGORITHM_LEFT_SYMMETRIC:
N
NeilBrown 已提交
2042
			pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2043 2044
			qd_idx = (pd_idx + 1) % raid_disks;
			*dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
2045 2046
			break;
		case ALGORITHM_RIGHT_SYMMETRIC:
N
NeilBrown 已提交
2047
			pd_idx = sector_div(stripe2, raid_disks);
2048 2049
			qd_idx = (pd_idx + 1) % raid_disks;
			*dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
2050
			break;
2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065

		case ALGORITHM_PARITY_0:
			pd_idx = 0;
			qd_idx = 1;
			(*dd_idx) += 2;
			break;
		case ALGORITHM_PARITY_N:
			pd_idx = data_disks;
			qd_idx = data_disks + 1;
			break;

		case ALGORITHM_ROTATING_ZERO_RESTART:
			/* Exactly the same as RIGHT_ASYMMETRIC, but or
			 * of blocks for computing Q is different.
			 */
N
NeilBrown 已提交
2066
			pd_idx = sector_div(stripe2, raid_disks);
2067 2068 2069 2070 2071 2072
			qd_idx = pd_idx + 1;
			if (pd_idx == raid_disks-1) {
				(*dd_idx)++;	/* Q D D D P */
				qd_idx = 0;
			} else if (*dd_idx >= pd_idx)
				(*dd_idx) += 2; /* D D P Q D */
2073
			ddf_layout = 1;
2074 2075 2076 2077 2078 2079 2080
			break;

		case ALGORITHM_ROTATING_N_RESTART:
			/* Same a left_asymmetric, by first stripe is
			 * D D D P Q  rather than
			 * Q D D D P
			 */
N
NeilBrown 已提交
2081 2082
			stripe2 += 1;
			pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2083 2084 2085 2086 2087 2088
			qd_idx = pd_idx + 1;
			if (pd_idx == raid_disks-1) {
				(*dd_idx)++;	/* Q D D D P */
				qd_idx = 0;
			} else if (*dd_idx >= pd_idx)
				(*dd_idx) += 2; /* D D P Q D */
2089
			ddf_layout = 1;
2090 2091 2092 2093
			break;

		case ALGORITHM_ROTATING_N_CONTINUE:
			/* Same as left_symmetric but Q is before P */
N
NeilBrown 已提交
2094
			pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2095 2096
			qd_idx = (pd_idx + raid_disks - 1) % raid_disks;
			*dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
2097
			ddf_layout = 1;
2098 2099 2100 2101
			break;

		case ALGORITHM_LEFT_ASYMMETRIC_6:
			/* RAID5 left_asymmetric, with Q on last device */
N
NeilBrown 已提交
2102
			pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
2103 2104 2105 2106 2107 2108
			if (*dd_idx >= pd_idx)
				(*dd_idx)++;
			qd_idx = raid_disks - 1;
			break;

		case ALGORITHM_RIGHT_ASYMMETRIC_6:
N
NeilBrown 已提交
2109
			pd_idx = sector_div(stripe2, raid_disks-1);
2110 2111 2112 2113 2114 2115
			if (*dd_idx >= pd_idx)
				(*dd_idx)++;
			qd_idx = raid_disks - 1;
			break;

		case ALGORITHM_LEFT_SYMMETRIC_6:
N
NeilBrown 已提交
2116
			pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
2117 2118 2119 2120 2121
			*dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
			qd_idx = raid_disks - 1;
			break;

		case ALGORITHM_RIGHT_SYMMETRIC_6:
N
NeilBrown 已提交
2122
			pd_idx = sector_div(stripe2, raid_disks-1);
2123 2124 2125 2126 2127 2128 2129 2130 2131 2132
			*dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
			qd_idx = raid_disks - 1;
			break;

		case ALGORITHM_PARITY_0_6:
			pd_idx = 0;
			(*dd_idx)++;
			qd_idx = raid_disks - 1;
			break;

2133
		default:
2134
			BUG();
2135 2136
		}
		break;
L
Linus Torvalds 已提交
2137 2138
	}

2139 2140 2141
	if (sh) {
		sh->pd_idx = pd_idx;
		sh->qd_idx = qd_idx;
2142
		sh->ddf_layout = ddf_layout;
2143
	}
L
Linus Torvalds 已提交
2144 2145 2146 2147 2148 2149 2150 2151
	/*
	 * Finally, compute the new sector number
	 */
	new_sector = (sector_t)stripe * sectors_per_chunk + chunk_offset;
	return new_sector;
}


2152
static sector_t compute_blocknr(struct stripe_head *sh, int i, int previous)
L
Linus Torvalds 已提交
2153
{
2154
	struct r5conf *conf = sh->raid_conf;
2155 2156
	int raid_disks = sh->disks;
	int data_disks = raid_disks - conf->max_degraded;
L
Linus Torvalds 已提交
2157
	sector_t new_sector = sh->sector, check;
2158 2159
	int sectors_per_chunk = previous ? conf->prev_chunk_sectors
					 : conf->chunk_sectors;
2160 2161
	int algorithm = previous ? conf->prev_algo
				 : conf->algorithm;
L
Linus Torvalds 已提交
2162 2163
	sector_t stripe;
	int chunk_offset;
2164 2165
	sector_t chunk_number;
	int dummy1, dd_idx = i;
L
Linus Torvalds 已提交
2166
	sector_t r_sector;
2167
	struct stripe_head sh2;
L
Linus Torvalds 已提交
2168

2169

L
Linus Torvalds 已提交
2170 2171 2172
	chunk_offset = sector_div(new_sector, sectors_per_chunk);
	stripe = new_sector;

2173 2174 2175 2176 2177
	if (i == sh->pd_idx)
		return 0;
	switch(conf->level) {
	case 4: break;
	case 5:
2178
		switch (algorithm) {
L
Linus Torvalds 已提交
2179 2180 2181 2182 2183 2184 2185 2186 2187 2188 2189
		case ALGORITHM_LEFT_ASYMMETRIC:
		case ALGORITHM_RIGHT_ASYMMETRIC:
			if (i > sh->pd_idx)
				i--;
			break;
		case ALGORITHM_LEFT_SYMMETRIC:
		case ALGORITHM_RIGHT_SYMMETRIC:
			if (i < sh->pd_idx)
				i += raid_disks;
			i -= (sh->pd_idx + 1);
			break;
2190 2191 2192 2193 2194
		case ALGORITHM_PARITY_0:
			i -= 1;
			break;
		case ALGORITHM_PARITY_N:
			break;
L
Linus Torvalds 已提交
2195
		default:
2196
			BUG();
2197 2198 2199
		}
		break;
	case 6:
2200
		if (i == sh->qd_idx)
2201
			return 0; /* It is the Q disk */
2202
		switch (algorithm) {
2203 2204
		case ALGORITHM_LEFT_ASYMMETRIC:
		case ALGORITHM_RIGHT_ASYMMETRIC:
2205 2206 2207 2208
		case ALGORITHM_ROTATING_ZERO_RESTART:
		case ALGORITHM_ROTATING_N_RESTART:
			if (sh->pd_idx == raid_disks-1)
				i--;	/* Q D D D P */
2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219 2220 2221 2222
			else if (i > sh->pd_idx)
				i -= 2; /* D D P Q D */
			break;
		case ALGORITHM_LEFT_SYMMETRIC:
		case ALGORITHM_RIGHT_SYMMETRIC:
			if (sh->pd_idx == raid_disks-1)
				i--; /* Q D D D P */
			else {
				/* D D P Q D */
				if (i < sh->pd_idx)
					i += raid_disks;
				i -= (sh->pd_idx + 2);
			}
			break;
2223 2224 2225 2226 2227 2228
		case ALGORITHM_PARITY_0:
			i -= 2;
			break;
		case ALGORITHM_PARITY_N:
			break;
		case ALGORITHM_ROTATING_N_CONTINUE:
2229
			/* Like left_symmetric, but P is before Q */
2230 2231
			if (sh->pd_idx == 0)
				i--;	/* P D D D Q */
2232 2233 2234 2235 2236 2237
			else {
				/* D D Q P D */
				if (i < sh->pd_idx)
					i += raid_disks;
				i -= (sh->pd_idx + 1);
			}
2238 2239 2240 2241 2242 2243 2244 2245 2246 2247 2248 2249 2250 2251 2252
			break;
		case ALGORITHM_LEFT_ASYMMETRIC_6:
		case ALGORITHM_RIGHT_ASYMMETRIC_6:
			if (i > sh->pd_idx)
				i--;
			break;
		case ALGORITHM_LEFT_SYMMETRIC_6:
		case ALGORITHM_RIGHT_SYMMETRIC_6:
			if (i < sh->pd_idx)
				i += data_disks + 1;
			i -= (sh->pd_idx + 1);
			break;
		case ALGORITHM_PARITY_0_6:
			i -= 1;
			break;
2253
		default:
2254
			BUG();
2255 2256
		}
		break;
L
Linus Torvalds 已提交
2257 2258 2259
	}

	chunk_number = stripe * data_disks + i;
2260
	r_sector = chunk_number * sectors_per_chunk + chunk_offset;
L
Linus Torvalds 已提交
2261

2262
	check = raid5_compute_sector(conf, r_sector,
2263
				     previous, &dummy1, &sh2);
2264 2265
	if (check != sh->sector || dummy1 != dd_idx || sh2.pd_idx != sh->pd_idx
		|| sh2.qd_idx != sh->qd_idx) {
2266 2267
		printk(KERN_ERR "md/raid:%s: compute_blocknr: map not correct\n",
		       mdname(conf->mddev));
L
Linus Torvalds 已提交
2268 2269 2270 2271 2272 2273
		return 0;
	}
	return r_sector;
}


2274
static void
2275
schedule_reconstruction(struct stripe_head *sh, struct stripe_head_state *s,
2276
			 int rcw, int expand)
2277 2278
{
	int i, pd_idx = sh->pd_idx, disks = sh->disks;
2279
	struct r5conf *conf = sh->raid_conf;
2280
	int level = conf->level;
2281 2282 2283 2284 2285 2286 2287

	if (rcw) {
		/* if we are not expanding this is a proper write request, and
		 * there will be bios with new data to be drained into the
		 * stripe cache
		 */
		if (!expand) {
2288 2289 2290 2291
			sh->reconstruct_state = reconstruct_state_drain_run;
			set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
		} else
			sh->reconstruct_state = reconstruct_state_run;
2292

2293
		set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
2294 2295 2296 2297 2298 2299

		for (i = disks; i--; ) {
			struct r5dev *dev = &sh->dev[i];

			if (dev->towrite) {
				set_bit(R5_LOCKED, &dev->flags);
2300
				set_bit(R5_Wantdrain, &dev->flags);
2301 2302
				if (!expand)
					clear_bit(R5_UPTODATE, &dev->flags);
2303
				s->locked++;
2304 2305
			}
		}
2306
		if (s->locked + conf->max_degraded == disks)
2307
			if (!test_and_set_bit(STRIPE_FULL_WRITE, &sh->state))
2308
				atomic_inc(&conf->pending_full_writes);
2309
	} else {
2310
		BUG_ON(level == 6);
2311 2312 2313
		BUG_ON(!(test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags) ||
			test_bit(R5_Wantcompute, &sh->dev[pd_idx].flags)));

2314
		sh->reconstruct_state = reconstruct_state_prexor_drain_run;
2315 2316
		set_bit(STRIPE_OP_PREXOR, &s->ops_request);
		set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
2317
		set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
2318 2319 2320 2321 2322 2323 2324 2325

		for (i = disks; i--; ) {
			struct r5dev *dev = &sh->dev[i];
			if (i == pd_idx)
				continue;

			if (dev->towrite &&
			    (test_bit(R5_UPTODATE, &dev->flags) ||
2326 2327
			     test_bit(R5_Wantcompute, &dev->flags))) {
				set_bit(R5_Wantdrain, &dev->flags);
2328 2329
				set_bit(R5_LOCKED, &dev->flags);
				clear_bit(R5_UPTODATE, &dev->flags);
2330
				s->locked++;
2331 2332 2333 2334
			}
		}
	}

2335
	/* keep the parity disk(s) locked while asynchronous operations
2336 2337 2338 2339
	 * are in flight
	 */
	set_bit(R5_LOCKED, &sh->dev[pd_idx].flags);
	clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
2340
	s->locked++;
2341

2342 2343 2344 2345 2346 2347 2348 2349 2350
	if (level == 6) {
		int qd_idx = sh->qd_idx;
		struct r5dev *dev = &sh->dev[qd_idx];

		set_bit(R5_LOCKED, &dev->flags);
		clear_bit(R5_UPTODATE, &dev->flags);
		s->locked++;
	}

2351
	pr_debug("%s: stripe %llu locked: %d ops_request: %lx\n",
2352
		__func__, (unsigned long long)sh->sector,
2353
		s->locked, s->ops_request);
2354
}
2355

L
Linus Torvalds 已提交
2356 2357
/*
 * Each stripe/dev can have one or more bion attached.
2358
 * toread/towrite point to the first in a chain.
L
Linus Torvalds 已提交
2359 2360 2361 2362 2363
 * The bi_next chain must be in order.
 */
static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, int forwrite)
{
	struct bio **bip;
2364
	struct r5conf *conf = sh->raid_conf;
2365
	int firstwrite=0;
L
Linus Torvalds 已提交
2366

2367
	pr_debug("adding bi b#%llu to stripe s#%llu\n",
L
Linus Torvalds 已提交
2368 2369 2370
		(unsigned long long)bi->bi_sector,
		(unsigned long long)sh->sector);

S
Shaohua Li 已提交
2371 2372 2373 2374 2375 2376 2377 2378 2379
	/*
	 * If several bio share a stripe. The bio bi_phys_segments acts as a
	 * reference count to avoid race. The reference count should already be
	 * increased before this function is called (for example, in
	 * make_request()), so other bio sharing this stripe will not free the
	 * stripe. If a stripe is owned by one stripe, the stripe lock will
	 * protect it.
	 */
	spin_lock_irq(&sh->stripe_lock);
2380
	if (forwrite) {
L
Linus Torvalds 已提交
2381
		bip = &sh->dev[dd_idx].towrite;
2382
		if (*bip == NULL)
2383 2384
			firstwrite = 1;
	} else
L
Linus Torvalds 已提交
2385 2386
		bip = &sh->dev[dd_idx].toread;
	while (*bip && (*bip)->bi_sector < bi->bi_sector) {
K
Kent Overstreet 已提交
2387
		if (bio_end_sector(*bip) > bi->bi_sector)
L
Linus Torvalds 已提交
2388 2389 2390
			goto overlap;
		bip = & (*bip)->bi_next;
	}
K
Kent Overstreet 已提交
2391
	if (*bip && (*bip)->bi_sector < bio_end_sector(bi))
L
Linus Torvalds 已提交
2392 2393
		goto overlap;

2394
	BUG_ON(*bip && bi->bi_next && (*bip) != bi->bi_next);
L
Linus Torvalds 已提交
2395 2396 2397
	if (*bip)
		bi->bi_next = *bip;
	*bip = bi;
2398
	raid5_inc_bi_active_stripes(bi);
2399

L
Linus Torvalds 已提交
2400 2401 2402 2403 2404 2405 2406
	if (forwrite) {
		/* check if page is covered */
		sector_t sector = sh->dev[dd_idx].sector;
		for (bi=sh->dev[dd_idx].towrite;
		     sector < sh->dev[dd_idx].sector + STRIPE_SECTORS &&
			     bi && bi->bi_sector <= sector;
		     bi = r5_next_bio(bi, sh->dev[dd_idx].sector)) {
K
Kent Overstreet 已提交
2407 2408
			if (bio_end_sector(bi) >= sector)
				sector = bio_end_sector(bi);
L
Linus Torvalds 已提交
2409 2410 2411 2412
		}
		if (sector >= sh->dev[dd_idx].sector + STRIPE_SECTORS)
			set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags);
	}
2413 2414 2415 2416

	pr_debug("added bi b#%llu to stripe s#%llu, disk %d.\n",
		(unsigned long long)(*bip)->bi_sector,
		(unsigned long long)sh->sector, dd_idx);
2417
	spin_unlock_irq(&sh->stripe_lock);
2418 2419 2420 2421 2422 2423 2424

	if (conf->mddev->bitmap && firstwrite) {
		bitmap_startwrite(conf->mddev->bitmap, sh->sector,
				  STRIPE_SECTORS, 0);
		sh->bm_seq = conf->seq_flush+1;
		set_bit(STRIPE_BIT_DELAY, &sh->state);
	}
L
Linus Torvalds 已提交
2425 2426 2427 2428
	return 1;

 overlap:
	set_bit(R5_Overlap, &sh->dev[dd_idx].flags);
S
Shaohua Li 已提交
2429
	spin_unlock_irq(&sh->stripe_lock);
L
Linus Torvalds 已提交
2430 2431 2432
	return 0;
}

2433
static void end_reshape(struct r5conf *conf);
2434

2435
static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
2436
			    struct stripe_head *sh)
2437
{
2438
	int sectors_per_chunk =
2439
		previous ? conf->prev_chunk_sectors : conf->chunk_sectors;
2440
	int dd_idx;
2441
	int chunk_offset = sector_div(stripe, sectors_per_chunk);
2442
	int disks = previous ? conf->previous_raid_disks : conf->raid_disks;
2443

2444 2445
	raid5_compute_sector(conf,
			     stripe * (disks - conf->max_degraded)
2446
			     *sectors_per_chunk + chunk_offset,
2447
			     previous,
2448
			     &dd_idx, sh);
2449 2450
}

2451
static void
2452
handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
2453 2454 2455 2456 2457 2458 2459 2460 2461
				struct stripe_head_state *s, int disks,
				struct bio **return_bi)
{
	int i;
	for (i = disks; i--; ) {
		struct bio *bi;
		int bitmap_end = 0;

		if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
2462
			struct md_rdev *rdev;
2463 2464 2465
			rcu_read_lock();
			rdev = rcu_dereference(conf->disks[i].rdev);
			if (rdev && test_bit(In_sync, &rdev->flags))
2466 2467 2468
				atomic_inc(&rdev->nr_pending);
			else
				rdev = NULL;
2469
			rcu_read_unlock();
2470 2471 2472 2473 2474 2475 2476 2477
			if (rdev) {
				if (!rdev_set_badblocks(
					    rdev,
					    sh->sector,
					    STRIPE_SECTORS, 0))
					md_error(conf->mddev, rdev);
				rdev_dec_pending(rdev, conf->mddev);
			}
2478
		}
S
Shaohua Li 已提交
2479
		spin_lock_irq(&sh->stripe_lock);
2480 2481 2482
		/* fail all writes first */
		bi = sh->dev[i].towrite;
		sh->dev[i].towrite = NULL;
S
Shaohua Li 已提交
2483
		spin_unlock_irq(&sh->stripe_lock);
2484
		if (bi)
2485 2486 2487 2488 2489 2490 2491 2492 2493
			bitmap_end = 1;

		if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
			wake_up(&conf->wait_for_overlap);

		while (bi && bi->bi_sector <
			sh->dev[i].sector + STRIPE_SECTORS) {
			struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector);
			clear_bit(BIO_UPTODATE, &bi->bi_flags);
2494
			if (!raid5_dec_bi_active_stripes(bi)) {
2495 2496 2497 2498 2499 2500
				md_write_end(conf->mddev);
				bi->bi_next = *return_bi;
				*return_bi = bi;
			}
			bi = nextbi;
		}
2501 2502 2503 2504
		if (bitmap_end)
			bitmap_endwrite(conf->mddev->bitmap, sh->sector,
				STRIPE_SECTORS, 0, 0);
		bitmap_end = 0;
2505 2506 2507 2508 2509 2510 2511 2512
		/* and fail all 'written' */
		bi = sh->dev[i].written;
		sh->dev[i].written = NULL;
		if (bi) bitmap_end = 1;
		while (bi && bi->bi_sector <
		       sh->dev[i].sector + STRIPE_SECTORS) {
			struct bio *bi2 = r5_next_bio(bi, sh->dev[i].sector);
			clear_bit(BIO_UPTODATE, &bi->bi_flags);
2513
			if (!raid5_dec_bi_active_stripes(bi)) {
2514 2515 2516 2517 2518 2519 2520
				md_write_end(conf->mddev);
				bi->bi_next = *return_bi;
				*return_bi = bi;
			}
			bi = bi2;
		}

2521 2522 2523 2524 2525 2526
		/* fail any reads if this device is non-operational and
		 * the data has not reached the cache yet.
		 */
		if (!test_bit(R5_Wantfill, &sh->dev[i].flags) &&
		    (!test_bit(R5_Insync, &sh->dev[i].flags) ||
		      test_bit(R5_ReadError, &sh->dev[i].flags))) {
2527
			spin_lock_irq(&sh->stripe_lock);
2528 2529
			bi = sh->dev[i].toread;
			sh->dev[i].toread = NULL;
2530
			spin_unlock_irq(&sh->stripe_lock);
2531 2532 2533 2534 2535 2536 2537
			if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
				wake_up(&conf->wait_for_overlap);
			while (bi && bi->bi_sector <
			       sh->dev[i].sector + STRIPE_SECTORS) {
				struct bio *nextbi =
					r5_next_bio(bi, sh->dev[i].sector);
				clear_bit(BIO_UPTODATE, &bi->bi_flags);
2538
				if (!raid5_dec_bi_active_stripes(bi)) {
2539 2540 2541 2542 2543 2544 2545 2546 2547
					bi->bi_next = *return_bi;
					*return_bi = bi;
				}
				bi = nextbi;
			}
		}
		if (bitmap_end)
			bitmap_endwrite(conf->mddev->bitmap, sh->sector,
					STRIPE_SECTORS, 0, 0);
2548 2549 2550 2551
		/* If we were in the middle of a write the parity block might
		 * still be locked - so just clear all R5_LOCKED flags
		 */
		clear_bit(R5_LOCKED, &sh->dev[i].flags);
2552 2553
	}

2554 2555 2556
	if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
		if (atomic_dec_and_test(&conf->pending_full_writes))
			md_wakeup_thread(conf->mddev->thread);
2557 2558
}

2559
static void
2560
handle_failed_sync(struct r5conf *conf, struct stripe_head *sh,
2561 2562 2563 2564 2565 2566 2567
		   struct stripe_head_state *s)
{
	int abort = 0;
	int i;

	clear_bit(STRIPE_SYNCING, &sh->state);
	s->syncing = 0;
2568
	s->replacing = 0;
2569
	/* There is nothing more to do for sync/check/repair.
2570 2571 2572
	 * Don't even need to abort as that is handled elsewhere
	 * if needed, and not always wanted e.g. if there is a known
	 * bad block here.
2573
	 * For recover/replace we need to record a bad block on all
2574 2575
	 * non-sync devices, or abort the recovery
	 */
2576 2577 2578 2579 2580 2581 2582 2583 2584 2585 2586 2587 2588 2589 2590 2591 2592 2593 2594 2595 2596 2597 2598
	if (test_bit(MD_RECOVERY_RECOVER, &conf->mddev->recovery)) {
		/* During recovery devices cannot be removed, so
		 * locking and refcounting of rdevs is not needed
		 */
		for (i = 0; i < conf->raid_disks; i++) {
			struct md_rdev *rdev = conf->disks[i].rdev;
			if (rdev
			    && !test_bit(Faulty, &rdev->flags)
			    && !test_bit(In_sync, &rdev->flags)
			    && !rdev_set_badblocks(rdev, sh->sector,
						   STRIPE_SECTORS, 0))
				abort = 1;
			rdev = conf->disks[i].replacement;
			if (rdev
			    && !test_bit(Faulty, &rdev->flags)
			    && !test_bit(In_sync, &rdev->flags)
			    && !rdev_set_badblocks(rdev, sh->sector,
						   STRIPE_SECTORS, 0))
				abort = 1;
		}
		if (abort)
			conf->recovery_disabled =
				conf->mddev->recovery_disabled;
2599
	}
2600
	md_done_sync(conf->mddev, STRIPE_SECTORS, !abort);
2601 2602
}

2603 2604 2605 2606 2607 2608 2609 2610 2611 2612 2613 2614 2615 2616 2617 2618
static int want_replace(struct stripe_head *sh, int disk_idx)
{
	struct md_rdev *rdev;
	int rv = 0;
	/* Doing recovery so rcu locking not required */
	rdev = sh->raid_conf->disks[disk_idx].replacement;
	if (rdev
	    && !test_bit(Faulty, &rdev->flags)
	    && !test_bit(In_sync, &rdev->flags)
	    && (rdev->recovery_offset <= sh->sector
		|| rdev->mddev->recovery_cp <= sh->sector))
		rv = 1;

	return rv;
}

2619
/* fetch_block - checks the given member device to see if its data needs
2620 2621 2622
 * to be read or computed to satisfy a request.
 *
 * Returns 1 when no more member devices need to be checked, otherwise returns
2623
 * 0 to tell the loop in handle_stripe_fill to continue
2624
 */
2625 2626
static int fetch_block(struct stripe_head *sh, struct stripe_head_state *s,
		       int disk_idx, int disks)
2627
{
2628
	struct r5dev *dev = &sh->dev[disk_idx];
2629 2630
	struct r5dev *fdev[2] = { &sh->dev[s->failed_num[0]],
				  &sh->dev[s->failed_num[1]] };
2631

2632
	/* is the data in this block needed, and can we get it? */
2633 2634 2635 2636 2637
	if (!test_bit(R5_LOCKED, &dev->flags) &&
	    !test_bit(R5_UPTODATE, &dev->flags) &&
	    (dev->toread ||
	     (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)) ||
	     s->syncing || s->expanding ||
2638
	     (s->replacing && want_replace(sh, disk_idx)) ||
2639 2640
	     (s->failed >= 1 && fdev[0]->toread) ||
	     (s->failed >= 2 && fdev[1]->toread) ||
2641 2642 2643
	     (sh->raid_conf->level <= 5 && s->failed && fdev[0]->towrite &&
	      !test_bit(R5_OVERWRITE, &fdev[0]->flags)) ||
	     (sh->raid_conf->level == 6 && s->failed && s->to_write))) {
2644 2645 2646 2647 2648 2649
		/* we would like to get this block, possibly by computing it,
		 * otherwise read it if the backing disk is insync
		 */
		BUG_ON(test_bit(R5_Wantcompute, &dev->flags));
		BUG_ON(test_bit(R5_Wantread, &dev->flags));
		if ((s->uptodate == disks - 1) &&
2650 2651
		    (s->failed && (disk_idx == s->failed_num[0] ||
				   disk_idx == s->failed_num[1]))) {
2652 2653
			/* have disk failed, and we're requested to fetch it;
			 * do compute it
2654
			 */
2655 2656 2657 2658 2659 2660 2661 2662
			pr_debug("Computing stripe %llu block %d\n",
			       (unsigned long long)sh->sector, disk_idx);
			set_bit(STRIPE_COMPUTE_RUN, &sh->state);
			set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
			set_bit(R5_Wantcompute, &dev->flags);
			sh->ops.target = disk_idx;
			sh->ops.target2 = -1; /* no 2nd target */
			s->req_compute = 1;
2663 2664 2665 2666 2667 2668
			/* Careful: from this point on 'uptodate' is in the eye
			 * of raid_run_ops which services 'compute' operations
			 * before writes. R5_Wantcompute flags a block that will
			 * be R5_UPTODATE by the time it is needed for a
			 * subsequent operation.
			 */
2669 2670 2671 2672 2673 2674 2675 2676 2677 2678 2679 2680 2681
			s->uptodate++;
			return 1;
		} else if (s->uptodate == disks-2 && s->failed >= 2) {
			/* Computing 2-failure is *very* expensive; only
			 * do it if failed >= 2
			 */
			int other;
			for (other = disks; other--; ) {
				if (other == disk_idx)
					continue;
				if (!test_bit(R5_UPTODATE,
				      &sh->dev[other].flags))
					break;
2682
			}
2683 2684 2685 2686 2687 2688 2689 2690 2691 2692 2693 2694 2695 2696 2697 2698 2699 2700 2701
			BUG_ON(other < 0);
			pr_debug("Computing stripe %llu blocks %d,%d\n",
			       (unsigned long long)sh->sector,
			       disk_idx, other);
			set_bit(STRIPE_COMPUTE_RUN, &sh->state);
			set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
			set_bit(R5_Wantcompute, &sh->dev[disk_idx].flags);
			set_bit(R5_Wantcompute, &sh->dev[other].flags);
			sh->ops.target = disk_idx;
			sh->ops.target2 = other;
			s->uptodate += 2;
			s->req_compute = 1;
			return 1;
		} else if (test_bit(R5_Insync, &dev->flags)) {
			set_bit(R5_LOCKED, &dev->flags);
			set_bit(R5_Wantread, &dev->flags);
			s->locked++;
			pr_debug("Reading block %d (sync=%d)\n",
				disk_idx, s->syncing);
2702 2703
		}
	}
2704 2705 2706 2707 2708

	return 0;
}

/**
2709
 * handle_stripe_fill - read or compute data to satisfy pending requests.
2710
 */
2711 2712 2713
static void handle_stripe_fill(struct stripe_head *sh,
			       struct stripe_head_state *s,
			       int disks)
2714 2715 2716 2717 2718 2719 2720 2721 2722 2723
{
	int i;

	/* look for blocks to read/compute, skip this if a compute
	 * is already in flight, or if the stripe contents are in the
	 * midst of changing due to a write
	 */
	if (!test_bit(STRIPE_COMPUTE_RUN, &sh->state) && !sh->check_state &&
	    !sh->reconstruct_state)
		for (i = disks; i--; )
2724
			if (fetch_block(sh, s, i, disks))
2725
				break;
2726 2727 2728 2729
	set_bit(STRIPE_HANDLE, &sh->state);
}


2730
/* handle_stripe_clean_event
2731 2732 2733 2734
 * any written block on an uptodate or failed drive can be returned.
 * Note that if we 'wrote' to a failed drive, it will be UPTODATE, but
 * never LOCKED, so we don't need to test 'failed' directly.
 */
2735
static void handle_stripe_clean_event(struct r5conf *conf,
2736 2737 2738 2739 2740 2741 2742 2743 2744
	struct stripe_head *sh, int disks, struct bio **return_bi)
{
	int i;
	struct r5dev *dev;

	for (i = disks; i--; )
		if (sh->dev[i].written) {
			dev = &sh->dev[i];
			if (!test_bit(R5_LOCKED, &dev->flags) &&
2745
			    (test_bit(R5_UPTODATE, &dev->flags) ||
2746
			     test_bit(R5_Discard, &dev->flags))) {
2747 2748
				/* We can return any write requests */
				struct bio *wbi, *wbi2;
2749
				pr_debug("Return write for disc %d\n", i);
2750 2751
				if (test_and_clear_bit(R5_Discard, &dev->flags))
					clear_bit(R5_UPTODATE, &dev->flags);
2752 2753 2754 2755 2756
				wbi = dev->written;
				dev->written = NULL;
				while (wbi && wbi->bi_sector <
					dev->sector + STRIPE_SECTORS) {
					wbi2 = r5_next_bio(wbi, dev->sector);
2757
					if (!raid5_dec_bi_active_stripes(wbi)) {
2758 2759 2760 2761 2762 2763
						md_write_end(conf->mddev);
						wbi->bi_next = *return_bi;
						*return_bi = wbi;
					}
					wbi = wbi2;
				}
2764 2765
				bitmap_endwrite(conf->mddev->bitmap, sh->sector,
						STRIPE_SECTORS,
2766
					 !test_bit(STRIPE_DEGRADED, &sh->state),
2767
						0);
2768
			}
2769 2770
		} else if (test_bit(R5_Discard, &sh->dev[i].flags))
			clear_bit(R5_Discard, &sh->dev[i].flags);
2771 2772 2773 2774

	if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
		if (atomic_dec_and_test(&conf->pending_full_writes))
			md_wakeup_thread(conf->mddev->thread);
2775 2776
}

2777
static void handle_stripe_dirtying(struct r5conf *conf,
2778 2779 2780
				   struct stripe_head *sh,
				   struct stripe_head_state *s,
				   int disks)
2781 2782
{
	int rmw = 0, rcw = 0, i;
2783 2784 2785 2786 2787 2788 2789 2790 2791 2792 2793 2794 2795
	sector_t recovery_cp = conf->mddev->recovery_cp;

	/* RAID6 requires 'rcw' in current implementation.
	 * Otherwise, check whether resync is now happening or should start.
	 * If yes, then the array is dirty (after unclean shutdown or
	 * initial creation), so parity in some stripes might be inconsistent.
	 * In this case, we need to always do reconstruct-write, to ensure
	 * that in case of drive failure or read-error correction, we
	 * generate correct data from the parity.
	 */
	if (conf->max_degraded == 2 ||
	    (recovery_cp < MaxSector && sh->sector >= recovery_cp)) {
		/* Calculate the real rcw later - for now make it
2796 2797 2798
		 * look like rcw is cheaper
		 */
		rcw = 1; rmw = 2;
2799 2800 2801
		pr_debug("force RCW max_degraded=%u, recovery_cp=%llu sh->sector=%llu\n",
			 conf->max_degraded, (unsigned long long)recovery_cp,
			 (unsigned long long)sh->sector);
2802
	} else for (i = disks; i--; ) {
2803 2804 2805 2806
		/* would I have to read this buffer for read_modify_write */
		struct r5dev *dev = &sh->dev[i];
		if ((dev->towrite || i == sh->pd_idx) &&
		    !test_bit(R5_LOCKED, &dev->flags) &&
2807 2808
		    !(test_bit(R5_UPTODATE, &dev->flags) ||
		      test_bit(R5_Wantcompute, &dev->flags))) {
2809 2810 2811 2812 2813 2814 2815 2816
			if (test_bit(R5_Insync, &dev->flags))
				rmw++;
			else
				rmw += 2*disks;  /* cannot read it */
		}
		/* Would I have to read this buffer for reconstruct_write */
		if (!test_bit(R5_OVERWRITE, &dev->flags) && i != sh->pd_idx &&
		    !test_bit(R5_LOCKED, &dev->flags) &&
2817 2818 2819
		    !(test_bit(R5_UPTODATE, &dev->flags) ||
		    test_bit(R5_Wantcompute, &dev->flags))) {
			if (test_bit(R5_Insync, &dev->flags)) rcw++;
2820 2821 2822 2823
			else
				rcw += 2*disks;
		}
	}
2824
	pr_debug("for sector %llu, rmw=%d rcw=%d\n",
2825 2826
		(unsigned long long)sh->sector, rmw, rcw);
	set_bit(STRIPE_HANDLE, &sh->state);
N
NeilBrown 已提交
2827
	if (rmw < rcw && rmw > 0) {
2828
		/* prefer read-modify-write, but need to get some data */
N
NeilBrown 已提交
2829 2830
		blk_add_trace_msg(conf->mddev->queue, "raid5 rmw %llu %d",
				  (unsigned long long)sh->sector, rmw);
2831 2832 2833 2834
		for (i = disks; i--; ) {
			struct r5dev *dev = &sh->dev[i];
			if ((dev->towrite || i == sh->pd_idx) &&
			    !test_bit(R5_LOCKED, &dev->flags) &&
2835 2836
			    !(test_bit(R5_UPTODATE, &dev->flags) ||
			    test_bit(R5_Wantcompute, &dev->flags)) &&
2837 2838 2839
			    test_bit(R5_Insync, &dev->flags)) {
				if (
				  test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
2840
					pr_debug("Read_old block "
N
NeilBrown 已提交
2841
						 "%d for r-m-w\n", i);
2842 2843 2844 2845 2846 2847 2848 2849 2850
					set_bit(R5_LOCKED, &dev->flags);
					set_bit(R5_Wantread, &dev->flags);
					s->locked++;
				} else {
					set_bit(STRIPE_DELAYED, &sh->state);
					set_bit(STRIPE_HANDLE, &sh->state);
				}
			}
		}
N
NeilBrown 已提交
2851
	}
2852
	if (rcw <= rmw && rcw > 0) {
2853
		/* want reconstruct write, but need to get some data */
N
NeilBrown 已提交
2854
		int qread =0;
2855
		rcw = 0;
2856 2857 2858
		for (i = disks; i--; ) {
			struct r5dev *dev = &sh->dev[i];
			if (!test_bit(R5_OVERWRITE, &dev->flags) &&
2859
			    i != sh->pd_idx && i != sh->qd_idx &&
2860
			    !test_bit(R5_LOCKED, &dev->flags) &&
2861
			    !(test_bit(R5_UPTODATE, &dev->flags) ||
2862 2863 2864 2865
			      test_bit(R5_Wantcompute, &dev->flags))) {
				rcw++;
				if (!test_bit(R5_Insync, &dev->flags))
					continue; /* it's a failed drive */
2866 2867
				if (
				  test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
2868
					pr_debug("Read_old block "
2869 2870 2871 2872
						"%d for Reconstruct\n", i);
					set_bit(R5_LOCKED, &dev->flags);
					set_bit(R5_Wantread, &dev->flags);
					s->locked++;
N
NeilBrown 已提交
2873
					qread++;
2874 2875 2876 2877 2878 2879
				} else {
					set_bit(STRIPE_DELAYED, &sh->state);
					set_bit(STRIPE_HANDLE, &sh->state);
				}
			}
		}
N
NeilBrown 已提交
2880 2881 2882 2883
		if (rcw)
			blk_add_trace_msg(conf->mddev->queue, "raid5 rcw %llu %d %d %d",
					  (unsigned long long)sh->sector,
					  rcw, qread, test_bit(STRIPE_DELAYED, &sh->state));
2884
	}
2885 2886 2887
	/* now if nothing is locked, and if we have enough data,
	 * we can start a write request
	 */
2888 2889
	/* since handle_stripe can be called at any time we need to handle the
	 * case where a compute block operation has been submitted and then a
2890 2891
	 * subsequent call wants to start a write request.  raid_run_ops only
	 * handles the case where compute block and reconstruct are requested
2892 2893 2894
	 * simultaneously.  If this is not the case then new writes need to be
	 * held off until the compute completes.
	 */
2895 2896 2897
	if ((s->req_compute || !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) &&
	    (s->locked == 0 && (rcw == 0 || rmw == 0) &&
	    !test_bit(STRIPE_BIT_DELAY, &sh->state)))
2898
		schedule_reconstruction(sh, s, rcw == 0, 0);
2899 2900
}

2901
static void handle_parity_checks5(struct r5conf *conf, struct stripe_head *sh,
2902 2903
				struct stripe_head_state *s, int disks)
{
2904
	struct r5dev *dev = NULL;
2905

2906
	set_bit(STRIPE_HANDLE, &sh->state);
2907

2908 2909 2910
	switch (sh->check_state) {
	case check_state_idle:
		/* start a new check operation if there are no failures */
2911 2912
		if (s->failed == 0) {
			BUG_ON(s->uptodate != disks);
2913 2914
			sh->check_state = check_state_run;
			set_bit(STRIPE_OP_CHECK, &s->ops_request);
2915 2916
			clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
			s->uptodate--;
2917
			break;
2918
		}
2919
		dev = &sh->dev[s->failed_num[0]];
2920 2921 2922 2923 2924 2925 2926 2927 2928
		/* fall through */
	case check_state_compute_result:
		sh->check_state = check_state_idle;
		if (!dev)
			dev = &sh->dev[sh->pd_idx];

		/* check that a write has not made the stripe insync */
		if (test_bit(STRIPE_INSYNC, &sh->state))
			break;
D
Dan Williams 已提交
2929

2930 2931 2932 2933 2934
		/* either failed parity check, or recovery is happening */
		BUG_ON(!test_bit(R5_UPTODATE, &dev->flags));
		BUG_ON(s->uptodate != disks);

		set_bit(R5_LOCKED, &dev->flags);
2935
		s->locked++;
2936
		set_bit(R5_Wantwrite, &dev->flags);
2937

2938 2939
		clear_bit(STRIPE_DEGRADED, &sh->state);
		set_bit(STRIPE_INSYNC, &sh->state);
2940 2941 2942 2943 2944 2945 2946 2947 2948 2949 2950 2951 2952 2953 2954 2955
		break;
	case check_state_run:
		break; /* we will be called again upon completion */
	case check_state_check_result:
		sh->check_state = check_state_idle;

		/* if a failure occurred during the check operation, leave
		 * STRIPE_INSYNC not set and let the stripe be handled again
		 */
		if (s->failed)
			break;

		/* handle a successful check operation, if parity is correct
		 * we are done.  Otherwise update the mismatch count and repair
		 * parity if !MD_RECOVERY_CHECK
		 */
D
Dan Williams 已提交
2956
		if ((sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) == 0)
2957 2958 2959 2960 2961
			/* parity is correct (on disc,
			 * not in buffer any more)
			 */
			set_bit(STRIPE_INSYNC, &sh->state);
		else {
2962
			atomic64_add(STRIPE_SECTORS, &conf->mddev->resync_mismatches);
2963 2964 2965 2966 2967
			if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery))
				/* don't try to repair!! */
				set_bit(STRIPE_INSYNC, &sh->state);
			else {
				sh->check_state = check_state_compute_run;
2968
				set_bit(STRIPE_COMPUTE_RUN, &sh->state);
2969 2970 2971 2972
				set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
				set_bit(R5_Wantcompute,
					&sh->dev[sh->pd_idx].flags);
				sh->ops.target = sh->pd_idx;
2973
				sh->ops.target2 = -1;
2974 2975 2976 2977 2978 2979 2980 2981 2982 2983 2984
				s->uptodate++;
			}
		}
		break;
	case check_state_compute_run:
		break;
	default:
		printk(KERN_ERR "%s: unknown check_state: %d sector: %llu\n",
		       __func__, sh->check_state,
		       (unsigned long long) sh->sector);
		BUG();
2985 2986 2987 2988
	}
}


2989
static void handle_parity_checks6(struct r5conf *conf, struct stripe_head *sh,
2990
				  struct stripe_head_state *s,
2991
				  int disks)
2992 2993
{
	int pd_idx = sh->pd_idx;
N
NeilBrown 已提交
2994
	int qd_idx = sh->qd_idx;
2995
	struct r5dev *dev;
2996 2997 2998 2999

	set_bit(STRIPE_HANDLE, &sh->state);

	BUG_ON(s->failed > 2);
3000

3001 3002 3003 3004 3005 3006
	/* Want to check and possibly repair P and Q.
	 * However there could be one 'failed' device, in which
	 * case we can only check one of them, possibly using the
	 * other to generate missing data
	 */

3007 3008 3009
	switch (sh->check_state) {
	case check_state_idle:
		/* start a new check operation if there are < 2 failures */
3010
		if (s->failed == s->q_failed) {
3011
			/* The only possible failed device holds Q, so it
3012 3013 3014
			 * makes sense to check P (If anything else were failed,
			 * we would have used P to recreate it).
			 */
3015
			sh->check_state = check_state_run;
3016
		}
3017
		if (!s->q_failed && s->failed < 2) {
3018
			/* Q is not failed, and we didn't use it to generate
3019 3020
			 * anything, so it makes sense to check it
			 */
3021 3022 3023 3024
			if (sh->check_state == check_state_run)
				sh->check_state = check_state_run_pq;
			else
				sh->check_state = check_state_run_q;
3025 3026
		}

3027 3028
		/* discard potentially stale zero_sum_result */
		sh->ops.zero_sum_result = 0;
3029

3030 3031 3032 3033
		if (sh->check_state == check_state_run) {
			/* async_xor_zero_sum destroys the contents of P */
			clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
			s->uptodate--;
3034
		}
3035 3036 3037 3038 3039 3040 3041
		if (sh->check_state >= check_state_run &&
		    sh->check_state <= check_state_run_pq) {
			/* async_syndrome_zero_sum preserves P and Q, so
			 * no need to mark them !uptodate here
			 */
			set_bit(STRIPE_OP_CHECK, &s->ops_request);
			break;
3042 3043
		}

3044 3045 3046 3047 3048
		/* we have 2-disk failure */
		BUG_ON(s->failed != 2);
		/* fall through */
	case check_state_compute_result:
		sh->check_state = check_state_idle;
3049

3050 3051 3052
		/* check that a write has not made the stripe insync */
		if (test_bit(STRIPE_INSYNC, &sh->state))
			break;
3053 3054

		/* now write out any block on a failed drive,
3055
		 * or P or Q if they were recomputed
3056
		 */
3057
		BUG_ON(s->uptodate < disks - 1); /* We don't need Q to recover */
3058
		if (s->failed == 2) {
3059
			dev = &sh->dev[s->failed_num[1]];
3060 3061 3062 3063 3064
			s->locked++;
			set_bit(R5_LOCKED, &dev->flags);
			set_bit(R5_Wantwrite, &dev->flags);
		}
		if (s->failed >= 1) {
3065
			dev = &sh->dev[s->failed_num[0]];
3066 3067 3068 3069
			s->locked++;
			set_bit(R5_LOCKED, &dev->flags);
			set_bit(R5_Wantwrite, &dev->flags);
		}
3070
		if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
3071 3072 3073 3074 3075
			dev = &sh->dev[pd_idx];
			s->locked++;
			set_bit(R5_LOCKED, &dev->flags);
			set_bit(R5_Wantwrite, &dev->flags);
		}
3076
		if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
3077 3078 3079 3080 3081 3082 3083 3084
			dev = &sh->dev[qd_idx];
			s->locked++;
			set_bit(R5_LOCKED, &dev->flags);
			set_bit(R5_Wantwrite, &dev->flags);
		}
		clear_bit(STRIPE_DEGRADED, &sh->state);

		set_bit(STRIPE_INSYNC, &sh->state);
3085 3086 3087 3088 3089 3090 3091 3092 3093 3094 3095 3096 3097 3098 3099 3100 3101 3102 3103 3104 3105 3106 3107 3108 3109 3110 3111 3112 3113
		break;
	case check_state_run:
	case check_state_run_q:
	case check_state_run_pq:
		break; /* we will be called again upon completion */
	case check_state_check_result:
		sh->check_state = check_state_idle;

		/* handle a successful check operation, if parity is correct
		 * we are done.  Otherwise update the mismatch count and repair
		 * parity if !MD_RECOVERY_CHECK
		 */
		if (sh->ops.zero_sum_result == 0) {
			/* both parities are correct */
			if (!s->failed)
				set_bit(STRIPE_INSYNC, &sh->state);
			else {
				/* in contrast to the raid5 case we can validate
				 * parity, but still have a failure to write
				 * back
				 */
				sh->check_state = check_state_compute_result;
				/* Returning at this point means that we may go
				 * off and bring p and/or q uptodate again so
				 * we make sure to check zero_sum_result again
				 * to verify if p or q need writeback
				 */
			}
		} else {
3114
			atomic64_add(STRIPE_SECTORS, &conf->mddev->resync_mismatches);
3115 3116 3117 3118 3119 3120 3121 3122 3123 3124 3125 3126 3127 3128 3129 3130 3131 3132 3133 3134 3135 3136 3137 3138 3139 3140 3141 3142 3143 3144 3145 3146 3147 3148
			if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery))
				/* don't try to repair!! */
				set_bit(STRIPE_INSYNC, &sh->state);
			else {
				int *target = &sh->ops.target;

				sh->ops.target = -1;
				sh->ops.target2 = -1;
				sh->check_state = check_state_compute_run;
				set_bit(STRIPE_COMPUTE_RUN, &sh->state);
				set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
				if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
					set_bit(R5_Wantcompute,
						&sh->dev[pd_idx].flags);
					*target = pd_idx;
					target = &sh->ops.target2;
					s->uptodate++;
				}
				if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
					set_bit(R5_Wantcompute,
						&sh->dev[qd_idx].flags);
					*target = qd_idx;
					s->uptodate++;
				}
			}
		}
		break;
	case check_state_compute_run:
		break;
	default:
		printk(KERN_ERR "%s: unknown check_state: %d sector: %llu\n",
		       __func__, sh->check_state,
		       (unsigned long long) sh->sector);
		BUG();
3149 3150 3151
	}
}

3152
static void handle_stripe_expansion(struct r5conf *conf, struct stripe_head *sh)
3153 3154 3155 3156 3157 3158
{
	int i;

	/* We have read all the blocks in this stripe and now we need to
	 * copy some of them into a target stripe for expand.
	 */
3159
	struct dma_async_tx_descriptor *tx = NULL;
3160 3161
	clear_bit(STRIPE_EXPAND_SOURCE, &sh->state);
	for (i = 0; i < sh->disks; i++)
N
NeilBrown 已提交
3162
		if (i != sh->pd_idx && i != sh->qd_idx) {
3163
			int dd_idx, j;
3164
			struct stripe_head *sh2;
3165
			struct async_submit_ctl submit;
3166

3167
			sector_t bn = compute_blocknr(sh, i, 1);
3168 3169
			sector_t s = raid5_compute_sector(conf, bn, 0,
							  &dd_idx, NULL);
3170
			sh2 = get_active_stripe(conf, s, 0, 1, 1);
3171 3172 3173 3174 3175 3176 3177 3178 3179 3180 3181 3182
			if (sh2 == NULL)
				/* so far only the early blocks of this stripe
				 * have been requested.  When later blocks
				 * get requested, we will try again
				 */
				continue;
			if (!test_bit(STRIPE_EXPANDING, &sh2->state) ||
			   test_bit(R5_Expanded, &sh2->dev[dd_idx].flags)) {
				/* must have already done this block */
				release_stripe(sh2);
				continue;
			}
3183 3184

			/* place all the copies on one channel */
3185
			init_async_submit(&submit, 0, tx, NULL, NULL, NULL);
3186
			tx = async_memcpy(sh2->dev[dd_idx].page,
3187
					  sh->dev[i].page, 0, 0, STRIPE_SIZE,
3188
					  &submit);
3189

3190 3191 3192 3193
			set_bit(R5_Expanded, &sh2->dev[dd_idx].flags);
			set_bit(R5_UPTODATE, &sh2->dev[dd_idx].flags);
			for (j = 0; j < conf->raid_disks; j++)
				if (j != sh2->pd_idx &&
3194
				    j != sh2->qd_idx &&
3195 3196 3197 3198 3199 3200 3201
				    !test_bit(R5_Expanded, &sh2->dev[j].flags))
					break;
			if (j == conf->raid_disks) {
				set_bit(STRIPE_EXPAND_READY, &sh2->state);
				set_bit(STRIPE_HANDLE, &sh2->state);
			}
			release_stripe(sh2);
3202

3203
		}
3204
	/* done submitting copies, wait for them to complete */
3205
	async_tx_quiesce(&tx);
3206
}
L
Linus Torvalds 已提交
3207 3208 3209 3210

/*
 * handle_stripe - do things to a stripe.
 *
3211 3212
 * We lock the stripe by setting STRIPE_ACTIVE and then examine the
 * state of various bits to see what needs to be done.
L
Linus Torvalds 已提交
3213
 * Possible results:
3214 3215
 *    return some read requests which now have data
 *    return some write requests which are safely on storage
L
Linus Torvalds 已提交
3216 3217 3218 3219 3220
 *    schedule a read on some buffers
 *    schedule a write of some buffers
 *    return confirmation of parity correctness
 *
 */
3221

3222
static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s)
L
Linus Torvalds 已提交
3223
{
3224
	struct r5conf *conf = sh->raid_conf;
3225
	int disks = sh->disks;
3226 3227
	struct r5dev *dev;
	int i;
3228
	int do_recovery = 0;
L
Linus Torvalds 已提交
3229

3230 3231 3232 3233 3234 3235
	memset(s, 0, sizeof(*s));

	s->expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state);
	s->expanded = test_bit(STRIPE_EXPAND_READY, &sh->state);
	s->failed_num[0] = -1;
	s->failed_num[1] = -1;
L
Linus Torvalds 已提交
3236

3237
	/* Now to look around and see what can be done */
L
Linus Torvalds 已提交
3238
	rcu_read_lock();
3239
	for (i=disks; i--; ) {
3240
		struct md_rdev *rdev;
3241 3242 3243
		sector_t first_bad;
		int bad_sectors;
		int is_bad = 0;
3244

3245
		dev = &sh->dev[i];
L
Linus Torvalds 已提交
3246

3247
		pr_debug("check %d: state 0x%lx read %p write %p written %p\n",
3248 3249
			 i, dev->flags,
			 dev->toread, dev->towrite, dev->written);
3250 3251 3252 3253 3254 3255 3256 3257
		/* maybe we can reply to a read
		 *
		 * new wantfill requests are only permitted while
		 * ops_complete_biofill is guaranteed to be inactive
		 */
		if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread &&
		    !test_bit(STRIPE_BIOFILL_RUN, &sh->state))
			set_bit(R5_Wantfill, &dev->flags);
L
Linus Torvalds 已提交
3258

3259
		/* now count some things */
3260 3261 3262 3263
		if (test_bit(R5_LOCKED, &dev->flags))
			s->locked++;
		if (test_bit(R5_UPTODATE, &dev->flags))
			s->uptodate++;
3264
		if (test_bit(R5_Wantcompute, &dev->flags)) {
3265 3266
			s->compute++;
			BUG_ON(s->compute > 2);
3267
		}
L
Linus Torvalds 已提交
3268

3269
		if (test_bit(R5_Wantfill, &dev->flags))
3270
			s->to_fill++;
3271
		else if (dev->toread)
3272
			s->to_read++;
3273
		if (dev->towrite) {
3274
			s->to_write++;
3275
			if (!test_bit(R5_OVERWRITE, &dev->flags))
3276
				s->non_overwrite++;
3277
		}
3278
		if (dev->written)
3279
			s->written++;
3280 3281 3282 3283 3284 3285 3286 3287 3288 3289
		/* Prefer to use the replacement for reads, but only
		 * if it is recovered enough and has no bad blocks.
		 */
		rdev = rcu_dereference(conf->disks[i].replacement);
		if (rdev && !test_bit(Faulty, &rdev->flags) &&
		    rdev->recovery_offset >= sh->sector + STRIPE_SECTORS &&
		    !is_badblock(rdev, sh->sector, STRIPE_SECTORS,
				 &first_bad, &bad_sectors))
			set_bit(R5_ReadRepl, &dev->flags);
		else {
3290 3291
			if (rdev)
				set_bit(R5_NeedReplace, &dev->flags);
3292 3293 3294
			rdev = rcu_dereference(conf->disks[i].rdev);
			clear_bit(R5_ReadRepl, &dev->flags);
		}
3295 3296
		if (rdev && test_bit(Faulty, &rdev->flags))
			rdev = NULL;
3297 3298 3299 3300 3301 3302 3303 3304 3305 3306 3307 3308
		if (rdev) {
			is_bad = is_badblock(rdev, sh->sector, STRIPE_SECTORS,
					     &first_bad, &bad_sectors);
			if (s->blocked_rdev == NULL
			    && (test_bit(Blocked, &rdev->flags)
				|| is_bad < 0)) {
				if (is_bad < 0)
					set_bit(BlockedBadBlocks,
						&rdev->flags);
				s->blocked_rdev = rdev;
				atomic_inc(&rdev->nr_pending);
			}
3309
		}
3310 3311 3312
		clear_bit(R5_Insync, &dev->flags);
		if (!rdev)
			/* Not in-sync */;
3313 3314
		else if (is_bad) {
			/* also not in-sync */
3315 3316
			if (!test_bit(WriteErrorSeen, &rdev->flags) &&
			    test_bit(R5_UPTODATE, &dev->flags)) {
3317 3318 3319 3320 3321 3322 3323
				/* treat as in-sync, but with a read error
				 * which we can now try to correct
				 */
				set_bit(R5_Insync, &dev->flags);
				set_bit(R5_ReadError, &dev->flags);
			}
		} else if (test_bit(In_sync, &rdev->flags))
3324
			set_bit(R5_Insync, &dev->flags);
3325
		else if (sh->sector + STRIPE_SECTORS <= rdev->recovery_offset)
3326
			/* in sync if before recovery_offset */
3327 3328 3329 3330 3331 3332 3333 3334 3335
			set_bit(R5_Insync, &dev->flags);
		else if (test_bit(R5_UPTODATE, &dev->flags) &&
			 test_bit(R5_Expanded, &dev->flags))
			/* If we've reshaped into here, we assume it is Insync.
			 * We will shortly update recovery_offset to make
			 * it official.
			 */
			set_bit(R5_Insync, &dev->flags);

A
Adam Kwolek 已提交
3336
		if (rdev && test_bit(R5_WriteError, &dev->flags)) {
3337 3338 3339 3340 3341 3342 3343
			/* This flag does not apply to '.replacement'
			 * only to .rdev, so make sure to check that*/
			struct md_rdev *rdev2 = rcu_dereference(
				conf->disks[i].rdev);
			if (rdev2 == rdev)
				clear_bit(R5_Insync, &dev->flags);
			if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
3344
				s->handle_bad_blocks = 1;
3345
				atomic_inc(&rdev2->nr_pending);
3346 3347 3348
			} else
				clear_bit(R5_WriteError, &dev->flags);
		}
A
Adam Kwolek 已提交
3349
		if (rdev && test_bit(R5_MadeGood, &dev->flags)) {
3350 3351 3352 3353 3354
			/* This flag does not apply to '.replacement'
			 * only to .rdev, so make sure to check that*/
			struct md_rdev *rdev2 = rcu_dereference(
				conf->disks[i].rdev);
			if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
3355
				s->handle_bad_blocks = 1;
3356
				atomic_inc(&rdev2->nr_pending);
3357 3358 3359
			} else
				clear_bit(R5_MadeGood, &dev->flags);
		}
3360 3361 3362 3363 3364 3365 3366 3367 3368
		if (test_bit(R5_MadeGoodRepl, &dev->flags)) {
			struct md_rdev *rdev2 = rcu_dereference(
				conf->disks[i].replacement);
			if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
				s->handle_bad_blocks = 1;
				atomic_inc(&rdev2->nr_pending);
			} else
				clear_bit(R5_MadeGoodRepl, &dev->flags);
		}
3369
		if (!test_bit(R5_Insync, &dev->flags)) {
3370 3371 3372
			/* The ReadError flag will just be confusing now */
			clear_bit(R5_ReadError, &dev->flags);
			clear_bit(R5_ReWrite, &dev->flags);
L
Linus Torvalds 已提交
3373
		}
3374 3375 3376
		if (test_bit(R5_ReadError, &dev->flags))
			clear_bit(R5_Insync, &dev->flags);
		if (!test_bit(R5_Insync, &dev->flags)) {
3377 3378 3379
			if (s->failed < 2)
				s->failed_num[s->failed] = i;
			s->failed++;
3380 3381
			if (rdev && !test_bit(Faulty, &rdev->flags))
				do_recovery = 1;
3382
		}
L
Linus Torvalds 已提交
3383
	}
3384 3385 3386 3387
	if (test_bit(STRIPE_SYNCING, &sh->state)) {
		/* If there is a failed device being replaced,
		 *     we must be recovering.
		 * else if we are after recovery_cp, we must be syncing
3388
		 * else if MD_RECOVERY_REQUESTED is set, we also are syncing.
3389 3390 3391 3392 3393
		 * else we can only be replacing
		 * sync and recovery both need to read all devices, and so
		 * use the same flag.
		 */
		if (do_recovery ||
3394 3395
		    sh->sector >= conf->mddev->recovery_cp ||
		    test_bit(MD_RECOVERY_REQUESTED, &(conf->mddev->recovery)))
3396 3397 3398 3399
			s->syncing = 1;
		else
			s->replacing = 1;
	}
L
Linus Torvalds 已提交
3400
	rcu_read_unlock();
3401 3402 3403 3404 3405
}

static void handle_stripe(struct stripe_head *sh)
{
	struct stripe_head_state s;
3406
	struct r5conf *conf = sh->raid_conf;
3407
	int i;
3408 3409
	int prexor;
	int disks = sh->disks;
3410
	struct r5dev *pdev, *qdev;
3411 3412

	clear_bit(STRIPE_HANDLE, &sh->state);
3413
	if (test_and_set_bit_lock(STRIPE_ACTIVE, &sh->state)) {
3414 3415 3416 3417 3418 3419 3420 3421 3422 3423 3424 3425 3426 3427 3428 3429 3430
		/* already being handled, ensure it gets handled
		 * again when current action finishes */
		set_bit(STRIPE_HANDLE, &sh->state);
		return;
	}

	if (test_and_clear_bit(STRIPE_SYNC_REQUESTED, &sh->state)) {
		set_bit(STRIPE_SYNCING, &sh->state);
		clear_bit(STRIPE_INSYNC, &sh->state);
	}
	clear_bit(STRIPE_DELAYED, &sh->state);

	pr_debug("handling stripe %llu, state=%#lx cnt=%d, "
		"pd_idx=%d, qd_idx=%d\n, check:%d, reconstruct:%d\n",
	       (unsigned long long)sh->sector, sh->state,
	       atomic_read(&sh->count), sh->pd_idx, sh->qd_idx,
	       sh->check_state, sh->reconstruct_state);
3431

3432
	analyse_stripe(sh, &s);
3433

3434 3435 3436 3437 3438
	if (s.handle_bad_blocks) {
		set_bit(STRIPE_HANDLE, &sh->state);
		goto finish;
	}

3439 3440
	if (unlikely(s.blocked_rdev)) {
		if (s.syncing || s.expanding || s.expanded ||
3441
		    s.replacing || s.to_write || s.written) {
3442 3443 3444 3445 3446 3447 3448 3449 3450 3451 3452 3453 3454 3455 3456 3457 3458 3459 3460 3461
			set_bit(STRIPE_HANDLE, &sh->state);
			goto finish;
		}
		/* There is nothing for the blocked_rdev to block */
		rdev_dec_pending(s.blocked_rdev, conf->mddev);
		s.blocked_rdev = NULL;
	}

	if (s.to_fill && !test_bit(STRIPE_BIOFILL_RUN, &sh->state)) {
		set_bit(STRIPE_OP_BIOFILL, &s.ops_request);
		set_bit(STRIPE_BIOFILL_RUN, &sh->state);
	}

	pr_debug("locked=%d uptodate=%d to_read=%d"
	       " to_write=%d failed=%d failed_num=%d,%d\n",
	       s.locked, s.uptodate, s.to_read, s.to_write, s.failed,
	       s.failed_num[0], s.failed_num[1]);
	/* check if the array has lost more than max_degraded devices and,
	 * if so, some requests might need to be failed.
	 */
3462 3463 3464 3465 3466
	if (s.failed > conf->max_degraded) {
		sh->check_state = 0;
		sh->reconstruct_state = 0;
		if (s.to_read+s.to_write+s.written)
			handle_failed_stripe(conf, sh, &s, disks, &s.return_bi);
3467
		if (s.syncing + s.replacing)
3468 3469
			handle_failed_sync(conf, sh, &s);
	}
3470

3471 3472 3473 3474 3475 3476 3477 3478 3479 3480 3481 3482 3483
	/* Now we check to see if any write operations have recently
	 * completed
	 */
	prexor = 0;
	if (sh->reconstruct_state == reconstruct_state_prexor_drain_result)
		prexor = 1;
	if (sh->reconstruct_state == reconstruct_state_drain_result ||
	    sh->reconstruct_state == reconstruct_state_prexor_drain_result) {
		sh->reconstruct_state = reconstruct_state_idle;

		/* All the 'written' buffers and the parity block are ready to
		 * be written back to disk
		 */
3484 3485
		BUG_ON(!test_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags) &&
		       !test_bit(R5_Discard, &sh->dev[sh->pd_idx].flags));
3486
		BUG_ON(sh->qd_idx >= 0 &&
3487 3488
		       !test_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags) &&
		       !test_bit(R5_Discard, &sh->dev[sh->qd_idx].flags));
3489 3490 3491 3492 3493 3494 3495 3496 3497 3498 3499 3500 3501 3502 3503 3504 3505 3506 3507
		for (i = disks; i--; ) {
			struct r5dev *dev = &sh->dev[i];
			if (test_bit(R5_LOCKED, &dev->flags) &&
				(i == sh->pd_idx || i == sh->qd_idx ||
				 dev->written)) {
				pr_debug("Writing block %d\n", i);
				set_bit(R5_Wantwrite, &dev->flags);
				if (prexor)
					continue;
				if (!test_bit(R5_Insync, &dev->flags) ||
				    ((i == sh->pd_idx || i == sh->qd_idx)  &&
				     s.failed == 0))
					set_bit(STRIPE_INSYNC, &sh->state);
			}
		}
		if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
			s.dec_preread_active = 1;
	}

3508 3509 3510 3511 3512 3513 3514 3515 3516 3517 3518 3519 3520 3521 3522 3523 3524 3525 3526 3527 3528 3529 3530 3531 3532 3533 3534 3535 3536 3537 3538 3539 3540 3541
	/*
	 * might be able to return some write requests if the parity blocks
	 * are safe, or on a failed drive
	 */
	pdev = &sh->dev[sh->pd_idx];
	s.p_failed = (s.failed >= 1 && s.failed_num[0] == sh->pd_idx)
		|| (s.failed >= 2 && s.failed_num[1] == sh->pd_idx);
	qdev = &sh->dev[sh->qd_idx];
	s.q_failed = (s.failed >= 1 && s.failed_num[0] == sh->qd_idx)
		|| (s.failed >= 2 && s.failed_num[1] == sh->qd_idx)
		|| conf->level < 6;

	if (s.written &&
	    (s.p_failed || ((test_bit(R5_Insync, &pdev->flags)
			     && !test_bit(R5_LOCKED, &pdev->flags)
			     && (test_bit(R5_UPTODATE, &pdev->flags) ||
				 test_bit(R5_Discard, &pdev->flags))))) &&
	    (s.q_failed || ((test_bit(R5_Insync, &qdev->flags)
			     && !test_bit(R5_LOCKED, &qdev->flags)
			     && (test_bit(R5_UPTODATE, &qdev->flags) ||
				 test_bit(R5_Discard, &qdev->flags))))))
		handle_stripe_clean_event(conf, sh, disks, &s.return_bi);

	/* Now we might consider reading some blocks, either to check/generate
	 * parity, or to satisfy requests
	 * or to load a block that is being partially written.
	 */
	if (s.to_read || s.non_overwrite
	    || (conf->level == 6 && s.to_write && s.failed)
	    || (s.syncing && (s.uptodate + s.compute < disks))
	    || s.replacing
	    || s.expanding)
		handle_stripe_fill(sh, &s, disks);

3542 3543 3544 3545 3546 3547 3548 3549 3550 3551 3552 3553 3554 3555 3556 3557 3558 3559 3560 3561 3562 3563 3564
	/* Now to consider new write requests and what else, if anything
	 * should be read.  We do not handle new writes when:
	 * 1/ A 'write' operation (copy+xor) is already in flight.
	 * 2/ A 'check' operation is in flight, as it may clobber the parity
	 *    block.
	 */
	if (s.to_write && !sh->reconstruct_state && !sh->check_state)
		handle_stripe_dirtying(conf, sh, &s, disks);

	/* maybe we need to check and possibly fix the parity for this stripe
	 * Any reads will already have been scheduled, so we just see if enough
	 * data is available.  The parity check is held off while parity
	 * dependent operations are in flight.
	 */
	if (sh->check_state ||
	    (s.syncing && s.locked == 0 &&
	     !test_bit(STRIPE_COMPUTE_RUN, &sh->state) &&
	     !test_bit(STRIPE_INSYNC, &sh->state))) {
		if (conf->level == 6)
			handle_parity_checks6(conf, sh, &s, disks);
		else
			handle_parity_checks5(conf, sh, &s, disks);
	}
3565

3566 3567 3568 3569 3570 3571 3572 3573 3574 3575 3576 3577 3578 3579
	if (s.replacing && s.locked == 0
	    && !test_bit(STRIPE_INSYNC, &sh->state)) {
		/* Write out to replacement devices where possible */
		for (i = 0; i < conf->raid_disks; i++)
			if (test_bit(R5_UPTODATE, &sh->dev[i].flags) &&
			    test_bit(R5_NeedReplace, &sh->dev[i].flags)) {
				set_bit(R5_WantReplace, &sh->dev[i].flags);
				set_bit(R5_LOCKED, &sh->dev[i].flags);
				s.locked++;
			}
		set_bit(STRIPE_INSYNC, &sh->state);
	}
	if ((s.syncing || s.replacing) && s.locked == 0 &&
	    test_bit(STRIPE_INSYNC, &sh->state)) {
3580 3581 3582 3583 3584 3585 3586 3587 3588 3589 3590 3591 3592 3593 3594 3595 3596 3597 3598 3599 3600 3601 3602 3603 3604 3605 3606 3607 3608
		md_done_sync(conf->mddev, STRIPE_SECTORS, 1);
		clear_bit(STRIPE_SYNCING, &sh->state);
	}

	/* If the failed drives are just a ReadError, then we might need
	 * to progress the repair/check process
	 */
	if (s.failed <= conf->max_degraded && !conf->mddev->ro)
		for (i = 0; i < s.failed; i++) {
			struct r5dev *dev = &sh->dev[s.failed_num[i]];
			if (test_bit(R5_ReadError, &dev->flags)
			    && !test_bit(R5_LOCKED, &dev->flags)
			    && test_bit(R5_UPTODATE, &dev->flags)
				) {
				if (!test_bit(R5_ReWrite, &dev->flags)) {
					set_bit(R5_Wantwrite, &dev->flags);
					set_bit(R5_ReWrite, &dev->flags);
					set_bit(R5_LOCKED, &dev->flags);
					s.locked++;
				} else {
					/* let's read it back */
					set_bit(R5_Wantread, &dev->flags);
					set_bit(R5_LOCKED, &dev->flags);
					s.locked++;
				}
			}
		}


3609 3610 3611 3612 3613 3614 3615 3616 3617 3618 3619 3620 3621 3622 3623 3624 3625 3626 3627 3628 3629 3630 3631 3632 3633 3634 3635
	/* Finish reconstruct operations initiated by the expansion process */
	if (sh->reconstruct_state == reconstruct_state_result) {
		struct stripe_head *sh_src
			= get_active_stripe(conf, sh->sector, 1, 1, 1);
		if (sh_src && test_bit(STRIPE_EXPAND_SOURCE, &sh_src->state)) {
			/* sh cannot be written until sh_src has been read.
			 * so arrange for sh to be delayed a little
			 */
			set_bit(STRIPE_DELAYED, &sh->state);
			set_bit(STRIPE_HANDLE, &sh->state);
			if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE,
					      &sh_src->state))
				atomic_inc(&conf->preread_active_stripes);
			release_stripe(sh_src);
			goto finish;
		}
		if (sh_src)
			release_stripe(sh_src);

		sh->reconstruct_state = reconstruct_state_idle;
		clear_bit(STRIPE_EXPANDING, &sh->state);
		for (i = conf->raid_disks; i--; ) {
			set_bit(R5_Wantwrite, &sh->dev[i].flags);
			set_bit(R5_LOCKED, &sh->dev[i].flags);
			s.locked++;
		}
	}
3636

3637 3638 3639 3640 3641 3642 3643 3644 3645 3646 3647 3648 3649 3650 3651 3652
	if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state) &&
	    !sh->reconstruct_state) {
		/* Need to write out all blocks after computing parity */
		sh->disks = conf->raid_disks;
		stripe_set_idx(sh->sector, conf, 0, sh);
		schedule_reconstruction(sh, &s, 1, 1);
	} else if (s.expanded && !sh->reconstruct_state && s.locked == 0) {
		clear_bit(STRIPE_EXPAND_READY, &sh->state);
		atomic_dec(&conf->reshape_stripes);
		wake_up(&conf->wait_for_overlap);
		md_done_sync(conf->mddev, STRIPE_SECTORS, 1);
	}

	if (s.expanding && s.locked == 0 &&
	    !test_bit(STRIPE_COMPUTE_RUN, &sh->state))
		handle_stripe_expansion(conf, sh);
3653

3654
finish:
3655
	/* wait for this device to become unblocked */
3656 3657 3658 3659 3660 3661 3662 3663 3664 3665 3666 3667
	if (unlikely(s.blocked_rdev)) {
		if (conf->mddev->external)
			md_wait_for_blocked_rdev(s.blocked_rdev,
						 conf->mddev);
		else
			/* Internal metadata will immediately
			 * be written by raid5d, so we don't
			 * need to wait here.
			 */
			rdev_dec_pending(s.blocked_rdev,
					 conf->mddev);
	}
3668

3669 3670
	if (s.handle_bad_blocks)
		for (i = disks; i--; ) {
3671
			struct md_rdev *rdev;
3672 3673 3674 3675 3676 3677 3678 3679 3680
			struct r5dev *dev = &sh->dev[i];
			if (test_and_clear_bit(R5_WriteError, &dev->flags)) {
				/* We own a safe reference to the rdev */
				rdev = conf->disks[i].rdev;
				if (!rdev_set_badblocks(rdev, sh->sector,
							STRIPE_SECTORS, 0))
					md_error(conf->mddev, rdev);
				rdev_dec_pending(rdev, conf->mddev);
			}
3681 3682 3683
			if (test_and_clear_bit(R5_MadeGood, &dev->flags)) {
				rdev = conf->disks[i].rdev;
				rdev_clear_badblocks(rdev, sh->sector,
3684
						     STRIPE_SECTORS, 0);
3685 3686
				rdev_dec_pending(rdev, conf->mddev);
			}
3687 3688
			if (test_and_clear_bit(R5_MadeGoodRepl, &dev->flags)) {
				rdev = conf->disks[i].replacement;
3689 3690 3691
				if (!rdev)
					/* rdev have been moved down */
					rdev = conf->disks[i].rdev;
3692
				rdev_clear_badblocks(rdev, sh->sector,
3693
						     STRIPE_SECTORS, 0);
3694 3695
				rdev_dec_pending(rdev, conf->mddev);
			}
3696 3697
		}

3698 3699 3700
	if (s.ops_request)
		raid_run_ops(sh, s.ops_request);

D
Dan Williams 已提交
3701
	ops_run_io(sh, &s);
3702

3703
	if (s.dec_preread_active) {
3704
		/* We delay this until after ops_run_io so that if make_request
T
Tejun Heo 已提交
3705
		 * is waiting on a flush, it won't continue until the writes
3706 3707 3708 3709 3710 3711 3712 3713
		 * have actually been submitted.
		 */
		atomic_dec(&conf->preread_active_stripes);
		if (atomic_read(&conf->preread_active_stripes) <
		    IO_THRESHOLD)
			md_wakeup_thread(conf->mddev->thread);
	}

3714
	return_io(s.return_bi);
3715

3716
	clear_bit_unlock(STRIPE_ACTIVE, &sh->state);
3717 3718
}

3719
static void raid5_activate_delayed(struct r5conf *conf)
3720 3721 3722 3723 3724 3725 3726 3727 3728 3729
{
	if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) {
		while (!list_empty(&conf->delayed_list)) {
			struct list_head *l = conf->delayed_list.next;
			struct stripe_head *sh;
			sh = list_entry(l, struct stripe_head, lru);
			list_del_init(l);
			clear_bit(STRIPE_DELAYED, &sh->state);
			if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
				atomic_inc(&conf->preread_active_stripes);
3730
			list_add_tail(&sh->lru, &conf->hold_list);
3731
		}
N
NeilBrown 已提交
3732
	}
3733 3734
}

3735
static void activate_bit_delay(struct r5conf *conf)
3736 3737 3738 3739 3740 3741 3742 3743 3744 3745 3746 3747 3748
{
	/* device_lock is held */
	struct list_head head;
	list_add(&head, &conf->bitmap_list);
	list_del_init(&conf->bitmap_list);
	while (!list_empty(&head)) {
		struct stripe_head *sh = list_entry(head.next, struct stripe_head, lru);
		list_del_init(&sh->lru);
		atomic_inc(&sh->count);
		__release_stripe(conf, sh);
	}
}

3749
int md_raid5_congested(struct mddev *mddev, int bits)
3750
{
3751
	struct r5conf *conf = mddev->private;
3752 3753 3754 3755

	/* No difference between reads and writes.  Just check
	 * how busy the stripe_cache is
	 */
3756

3757 3758 3759 3760 3761 3762 3763 3764 3765
	if (conf->inactive_blocked)
		return 1;
	if (conf->quiesce)
		return 1;
	if (list_empty_careful(&conf->inactive_list))
		return 1;

	return 0;
}
N
NeilBrown 已提交
3766 3767 3768 3769
EXPORT_SYMBOL_GPL(md_raid5_congested);

static int raid5_congested(void *data, int bits)
{
3770
	struct mddev *mddev = data;
N
NeilBrown 已提交
3771 3772 3773 3774

	return mddev_congested(mddev, bits) ||
		md_raid5_congested(mddev, bits);
}
3775

3776 3777 3778
/* We want read requests to align with chunks where possible,
 * but write requests don't need to.
 */
3779 3780 3781
static int raid5_mergeable_bvec(struct request_queue *q,
				struct bvec_merge_data *bvm,
				struct bio_vec *biovec)
3782
{
3783
	struct mddev *mddev = q->queuedata;
3784
	sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
3785
	int max;
3786
	unsigned int chunk_sectors = mddev->chunk_sectors;
3787
	unsigned int bio_sectors = bvm->bi_size >> 9;
3788

3789
	if ((bvm->bi_rw & 1) == WRITE)
3790 3791
		return biovec->bv_len; /* always allow writes to be mergeable */

3792 3793
	if (mddev->new_chunk_sectors < mddev->chunk_sectors)
		chunk_sectors = mddev->new_chunk_sectors;
3794 3795 3796 3797 3798 3799 3800 3801
	max =  (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9;
	if (max < 0) max = 0;
	if (max <= biovec->bv_len && bio_sectors == 0)
		return biovec->bv_len;
	else
		return max;
}

3802

3803
static int in_chunk_boundary(struct mddev *mddev, struct bio *bio)
3804 3805
{
	sector_t sector = bio->bi_sector + get_start_sect(bio->bi_bdev);
3806
	unsigned int chunk_sectors = mddev->chunk_sectors;
3807
	unsigned int bio_sectors = bio_sectors(bio);
3808

3809 3810
	if (mddev->new_chunk_sectors < mddev->chunk_sectors)
		chunk_sectors = mddev->new_chunk_sectors;
3811 3812 3813 3814
	return  chunk_sectors >=
		((sector & (chunk_sectors - 1)) + bio_sectors);
}

3815 3816 3817 3818
/*
 *  add bio to the retry LIFO  ( in O(1) ... we are in interrupt )
 *  later sampled by raid5d.
 */
3819
static void add_bio_to_retry(struct bio *bi,struct r5conf *conf)
3820 3821 3822 3823 3824 3825 3826 3827 3828 3829 3830 3831 3832
{
	unsigned long flags;

	spin_lock_irqsave(&conf->device_lock, flags);

	bi->bi_next = conf->retry_read_aligned_list;
	conf->retry_read_aligned_list = bi;

	spin_unlock_irqrestore(&conf->device_lock, flags);
	md_wakeup_thread(conf->mddev->thread);
}


3833
static struct bio *remove_bio_from_retry(struct r5conf *conf)
3834 3835 3836 3837 3838 3839 3840 3841 3842 3843
{
	struct bio *bi;

	bi = conf->retry_read_aligned;
	if (bi) {
		conf->retry_read_aligned = NULL;
		return bi;
	}
	bi = conf->retry_read_aligned_list;
	if(bi) {
3844
		conf->retry_read_aligned_list = bi->bi_next;
3845
		bi->bi_next = NULL;
3846 3847 3848 3849
		/*
		 * this sets the active strip count to 1 and the processed
		 * strip count to zero (upper 8 bits)
		 */
3850
		raid5_set_bi_stripes(bi, 1); /* biased count of active stripes */
3851 3852 3853 3854 3855 3856
	}

	return bi;
}


3857 3858 3859 3860 3861 3862
/*
 *  The "raid5_align_endio" should check if the read succeeded and if it
 *  did, call bio_endio on the original bio (having bio_put the new bio
 *  first).
 *  If the read failed..
 */
3863
static void raid5_align_endio(struct bio *bi, int error)
3864 3865
{
	struct bio* raid_bi  = bi->bi_private;
3866
	struct mddev *mddev;
3867
	struct r5conf *conf;
3868
	int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
3869
	struct md_rdev *rdev;
3870

3871
	bio_put(bi);
3872 3873 3874

	rdev = (void*)raid_bi->bi_next;
	raid_bi->bi_next = NULL;
3875 3876
	mddev = rdev->mddev;
	conf = mddev->private;
3877 3878 3879 3880

	rdev_dec_pending(rdev, conf->mddev);

	if (!error && uptodate) {
3881
		bio_endio(raid_bi, 0);
3882 3883
		if (atomic_dec_and_test(&conf->active_aligned_reads))
			wake_up(&conf->wait_for_stripe);
3884
		return;
3885 3886 3887
	}


3888
	pr_debug("raid5_align_endio : io error...handing IO for a retry\n");
3889 3890

	add_bio_to_retry(raid_bi, conf);
3891 3892
}

3893 3894
static int bio_fits_rdev(struct bio *bi)
{
3895
	struct request_queue *q = bdev_get_queue(bi->bi_bdev);
3896

3897
	if (bio_sectors(bi) > queue_max_sectors(q))
3898 3899
		return 0;
	blk_recount_segments(q, bi);
3900
	if (bi->bi_phys_segments > queue_max_segments(q))
3901 3902 3903 3904 3905 3906 3907 3908 3909 3910 3911 3912
		return 0;

	if (q->merge_bvec_fn)
		/* it's too hard to apply the merge_bvec_fn at this stage,
		 * just just give up
		 */
		return 0;

	return 1;
}


3913
static int chunk_aligned_read(struct mddev *mddev, struct bio * raid_bio)
3914
{
3915
	struct r5conf *conf = mddev->private;
N
NeilBrown 已提交
3916
	int dd_idx;
3917
	struct bio* align_bi;
3918
	struct md_rdev *rdev;
3919
	sector_t end_sector;
3920 3921

	if (!in_chunk_boundary(mddev, raid_bio)) {
3922
		pr_debug("chunk_aligned_read : non aligned\n");
3923 3924 3925
		return 0;
	}
	/*
3926
	 * use bio_clone_mddev to make a copy of the bio
3927
	 */
3928
	align_bi = bio_clone_mddev(raid_bio, GFP_NOIO, mddev);
3929 3930 3931 3932 3933 3934 3935 3936 3937 3938 3939
	if (!align_bi)
		return 0;
	/*
	 *   set bi_end_io to a new function, and set bi_private to the
	 *     original bio.
	 */
	align_bi->bi_end_io  = raid5_align_endio;
	align_bi->bi_private = raid_bio;
	/*
	 *	compute position
	 */
3940 3941
	align_bi->bi_sector =  raid5_compute_sector(conf, raid_bio->bi_sector,
						    0,
3942
						    &dd_idx, NULL);
3943

K
Kent Overstreet 已提交
3944
	end_sector = bio_end_sector(align_bi);
3945
	rcu_read_lock();
3946 3947 3948 3949 3950 3951 3952 3953 3954 3955 3956
	rdev = rcu_dereference(conf->disks[dd_idx].replacement);
	if (!rdev || test_bit(Faulty, &rdev->flags) ||
	    rdev->recovery_offset < end_sector) {
		rdev = rcu_dereference(conf->disks[dd_idx].rdev);
		if (rdev &&
		    (test_bit(Faulty, &rdev->flags) ||
		    !(test_bit(In_sync, &rdev->flags) ||
		      rdev->recovery_offset >= end_sector)))
			rdev = NULL;
	}
	if (rdev) {
3957 3958 3959
		sector_t first_bad;
		int bad_sectors;

3960 3961
		atomic_inc(&rdev->nr_pending);
		rcu_read_unlock();
3962 3963 3964 3965
		raid_bio->bi_next = (void*)rdev;
		align_bi->bi_bdev =  rdev->bdev;
		align_bi->bi_flags &= ~(1 << BIO_SEG_VALID);

3966
		if (!bio_fits_rdev(align_bi) ||
3967
		    is_badblock(rdev, align_bi->bi_sector, bio_sectors(align_bi),
3968 3969
				&first_bad, &bad_sectors)) {
			/* too big in some way, or has a known bad block */
3970 3971 3972 3973 3974
			bio_put(align_bi);
			rdev_dec_pending(rdev, mddev);
			return 0;
		}

3975 3976 3977
		/* No reshape active, so we can trust rdev->data_offset */
		align_bi->bi_sector += rdev->data_offset;

3978 3979 3980
		spin_lock_irq(&conf->device_lock);
		wait_event_lock_irq(conf->wait_for_stripe,
				    conf->quiesce == 0,
3981
				    conf->device_lock);
3982 3983 3984
		atomic_inc(&conf->active_aligned_reads);
		spin_unlock_irq(&conf->device_lock);

N
NeilBrown 已提交
3985 3986 3987
		trace_block_bio_remap(bdev_get_queue(align_bi->bi_bdev),
				      align_bi, disk_devt(mddev->gendisk),
				      raid_bio->bi_sector);
3988 3989 3990 3991
		generic_make_request(align_bi);
		return 1;
	} else {
		rcu_read_unlock();
3992
		bio_put(align_bi);
3993 3994 3995 3996
		return 0;
	}
}

3997 3998 3999 4000 4001 4002 4003 4004 4005 4006
/* __get_priority_stripe - get the next stripe to process
 *
 * Full stripe writes are allowed to pass preread active stripes up until
 * the bypass_threshold is exceeded.  In general the bypass_count
 * increments when the handle_list is handled before the hold_list; however, it
 * will not be incremented when STRIPE_IO_STARTED is sampled set signifying a
 * stripe with in flight i/o.  The bypass_count will be reset when the
 * head of the hold_list has changed, i.e. the head was promoted to the
 * handle_list.
 */
4007
static struct stripe_head *__get_priority_stripe(struct r5conf *conf)
4008 4009 4010 4011 4012 4013 4014 4015 4016 4017 4018 4019 4020 4021 4022 4023 4024 4025 4026 4027 4028 4029 4030 4031 4032 4033 4034 4035 4036 4037 4038 4039 4040 4041 4042 4043 4044 4045 4046 4047 4048
{
	struct stripe_head *sh;

	pr_debug("%s: handle: %s hold: %s full_writes: %d bypass_count: %d\n",
		  __func__,
		  list_empty(&conf->handle_list) ? "empty" : "busy",
		  list_empty(&conf->hold_list) ? "empty" : "busy",
		  atomic_read(&conf->pending_full_writes), conf->bypass_count);

	if (!list_empty(&conf->handle_list)) {
		sh = list_entry(conf->handle_list.next, typeof(*sh), lru);

		if (list_empty(&conf->hold_list))
			conf->bypass_count = 0;
		else if (!test_bit(STRIPE_IO_STARTED, &sh->state)) {
			if (conf->hold_list.next == conf->last_hold)
				conf->bypass_count++;
			else {
				conf->last_hold = conf->hold_list.next;
				conf->bypass_count -= conf->bypass_threshold;
				if (conf->bypass_count < 0)
					conf->bypass_count = 0;
			}
		}
	} else if (!list_empty(&conf->hold_list) &&
		   ((conf->bypass_threshold &&
		     conf->bypass_count > conf->bypass_threshold) ||
		    atomic_read(&conf->pending_full_writes) == 0)) {
		sh = list_entry(conf->hold_list.next,
				typeof(*sh), lru);
		conf->bypass_count -= conf->bypass_threshold;
		if (conf->bypass_count < 0)
			conf->bypass_count = 0;
	} else
		return NULL;

	list_del_init(&sh->lru);
	atomic_inc(&sh->count);
	BUG_ON(atomic_read(&sh->count) != 1);
	return sh;
}
4049

4050 4051 4052 4053 4054 4055 4056 4057 4058 4059 4060 4061
struct raid5_plug_cb {
	struct blk_plug_cb	cb;
	struct list_head	list;
};

static void raid5_unplug(struct blk_plug_cb *blk_cb, bool from_schedule)
{
	struct raid5_plug_cb *cb = container_of(
		blk_cb, struct raid5_plug_cb, cb);
	struct stripe_head *sh;
	struct mddev *mddev = cb->cb.data;
	struct r5conf *conf = mddev->private;
N
NeilBrown 已提交
4062
	int cnt = 0;
4063 4064 4065 4066 4067 4068 4069 4070 4071 4072 4073 4074 4075 4076

	if (cb->list.next && !list_empty(&cb->list)) {
		spin_lock_irq(&conf->device_lock);
		while (!list_empty(&cb->list)) {
			sh = list_first_entry(&cb->list, struct stripe_head, lru);
			list_del_init(&sh->lru);
			/*
			 * avoid race release_stripe_plug() sees
			 * STRIPE_ON_UNPLUG_LIST clear but the stripe
			 * is still in our list
			 */
			smp_mb__before_clear_bit();
			clear_bit(STRIPE_ON_UNPLUG_LIST, &sh->state);
			__release_stripe(conf, sh);
N
NeilBrown 已提交
4077
			cnt++;
4078 4079 4080
		}
		spin_unlock_irq(&conf->device_lock);
	}
N
NeilBrown 已提交
4081
	trace_block_unplug(mddev->queue, cnt, !from_schedule);
4082 4083 4084 4085 4086 4087 4088 4089 4090 4091 4092 4093 4094 4095 4096 4097 4098 4099 4100 4101 4102 4103 4104 4105 4106 4107 4108
	kfree(cb);
}

static void release_stripe_plug(struct mddev *mddev,
				struct stripe_head *sh)
{
	struct blk_plug_cb *blk_cb = blk_check_plugged(
		raid5_unplug, mddev,
		sizeof(struct raid5_plug_cb));
	struct raid5_plug_cb *cb;

	if (!blk_cb) {
		release_stripe(sh);
		return;
	}

	cb = container_of(blk_cb, struct raid5_plug_cb, cb);

	if (cb->list.next == NULL)
		INIT_LIST_HEAD(&cb->list);

	if (!test_and_set_bit(STRIPE_ON_UNPLUG_LIST, &sh->state))
		list_add_tail(&sh->lru, &cb->list);
	else
		release_stripe(sh);
}

S
Shaohua Li 已提交
4109 4110 4111 4112 4113 4114 4115 4116 4117 4118 4119 4120 4121 4122 4123 4124 4125 4126 4127 4128 4129 4130 4131 4132 4133 4134 4135 4136 4137 4138 4139 4140 4141 4142 4143 4144 4145 4146 4147 4148 4149 4150 4151 4152 4153 4154 4155 4156 4157 4158 4159 4160 4161 4162 4163 4164 4165 4166 4167 4168 4169 4170 4171 4172 4173 4174 4175 4176 4177 4178 4179 4180 4181 4182 4183 4184 4185 4186 4187 4188 4189 4190
static void make_discard_request(struct mddev *mddev, struct bio *bi)
{
	struct r5conf *conf = mddev->private;
	sector_t logical_sector, last_sector;
	struct stripe_head *sh;
	int remaining;
	int stripe_sectors;

	if (mddev->reshape_position != MaxSector)
		/* Skip discard while reshape is happening */
		return;

	logical_sector = bi->bi_sector & ~((sector_t)STRIPE_SECTORS-1);
	last_sector = bi->bi_sector + (bi->bi_size>>9);

	bi->bi_next = NULL;
	bi->bi_phys_segments = 1; /* over-loaded to count active stripes */

	stripe_sectors = conf->chunk_sectors *
		(conf->raid_disks - conf->max_degraded);
	logical_sector = DIV_ROUND_UP_SECTOR_T(logical_sector,
					       stripe_sectors);
	sector_div(last_sector, stripe_sectors);

	logical_sector *= conf->chunk_sectors;
	last_sector *= conf->chunk_sectors;

	for (; logical_sector < last_sector;
	     logical_sector += STRIPE_SECTORS) {
		DEFINE_WAIT(w);
		int d;
	again:
		sh = get_active_stripe(conf, logical_sector, 0, 0, 0);
		prepare_to_wait(&conf->wait_for_overlap, &w,
				TASK_UNINTERRUPTIBLE);
		spin_lock_irq(&sh->stripe_lock);
		for (d = 0; d < conf->raid_disks; d++) {
			if (d == sh->pd_idx || d == sh->qd_idx)
				continue;
			if (sh->dev[d].towrite || sh->dev[d].toread) {
				set_bit(R5_Overlap, &sh->dev[d].flags);
				spin_unlock_irq(&sh->stripe_lock);
				release_stripe(sh);
				schedule();
				goto again;
			}
		}
		finish_wait(&conf->wait_for_overlap, &w);
		for (d = 0; d < conf->raid_disks; d++) {
			if (d == sh->pd_idx || d == sh->qd_idx)
				continue;
			sh->dev[d].towrite = bi;
			set_bit(R5_OVERWRITE, &sh->dev[d].flags);
			raid5_inc_bi_active_stripes(bi);
		}
		spin_unlock_irq(&sh->stripe_lock);
		if (conf->mddev->bitmap) {
			for (d = 0;
			     d < conf->raid_disks - conf->max_degraded;
			     d++)
				bitmap_startwrite(mddev->bitmap,
						  sh->sector,
						  STRIPE_SECTORS,
						  0);
			sh->bm_seq = conf->seq_flush + 1;
			set_bit(STRIPE_BIT_DELAY, &sh->state);
		}

		set_bit(STRIPE_HANDLE, &sh->state);
		clear_bit(STRIPE_DELAYED, &sh->state);
		if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
			atomic_inc(&conf->preread_active_stripes);
		release_stripe_plug(mddev, sh);
	}

	remaining = raid5_dec_bi_active_stripes(bi);
	if (remaining == 0) {
		md_write_end(mddev);
		bio_endio(bi, 0);
	}
}

4191
static void make_request(struct mddev *mddev, struct bio * bi)
L
Linus Torvalds 已提交
4192
{
4193
	struct r5conf *conf = mddev->private;
4194
	int dd_idx;
L
Linus Torvalds 已提交
4195 4196 4197
	sector_t new_sector;
	sector_t logical_sector, last_sector;
	struct stripe_head *sh;
4198
	const int rw = bio_data_dir(bi);
4199
	int remaining;
L
Linus Torvalds 已提交
4200

T
Tejun Heo 已提交
4201 4202
	if (unlikely(bi->bi_rw & REQ_FLUSH)) {
		md_flush_request(mddev, bi);
4203
		return;
4204 4205
	}

4206
	md_write_start(mddev, bi);
4207

4208
	if (rw == READ &&
4209
	     mddev->reshape_position == MaxSector &&
4210
	     chunk_aligned_read(mddev,bi))
4211
		return;
4212

S
Shaohua Li 已提交
4213 4214 4215 4216 4217
	if (unlikely(bi->bi_rw & REQ_DISCARD)) {
		make_discard_request(mddev, bi);
		return;
	}

L
Linus Torvalds 已提交
4218
	logical_sector = bi->bi_sector & ~((sector_t)STRIPE_SECTORS-1);
K
Kent Overstreet 已提交
4219
	last_sector = bio_end_sector(bi);
L
Linus Torvalds 已提交
4220 4221
	bi->bi_next = NULL;
	bi->bi_phys_segments = 1;	/* over-loaded to count active stripes */
4222

L
Linus Torvalds 已提交
4223 4224
	for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) {
		DEFINE_WAIT(w);
4225
		int previous;
4226

4227
	retry:
4228
		previous = 0;
4229
		prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
4230
		if (unlikely(conf->reshape_progress != MaxSector)) {
4231
			/* spinlock is needed as reshape_progress may be
4232 4233
			 * 64bit on a 32bit platform, and so it might be
			 * possible to see a half-updated value
4234
			 * Of course reshape_progress could change after
4235 4236 4237 4238
			 * the lock is dropped, so once we get a reference
			 * to the stripe that we think it is, we will have
			 * to check again.
			 */
4239
			spin_lock_irq(&conf->device_lock);
4240
			if (mddev->reshape_backwards
4241 4242
			    ? logical_sector < conf->reshape_progress
			    : logical_sector >= conf->reshape_progress) {
4243 4244
				previous = 1;
			} else {
4245
				if (mddev->reshape_backwards
4246 4247
				    ? logical_sector < conf->reshape_safe
				    : logical_sector >= conf->reshape_safe) {
4248 4249 4250 4251 4252
					spin_unlock_irq(&conf->device_lock);
					schedule();
					goto retry;
				}
			}
4253 4254
			spin_unlock_irq(&conf->device_lock);
		}
4255

4256 4257
		new_sector = raid5_compute_sector(conf, logical_sector,
						  previous,
4258
						  &dd_idx, NULL);
4259
		pr_debug("raid456: make_request, sector %llu logical %llu\n",
L
Linus Torvalds 已提交
4260 4261 4262
			(unsigned long long)new_sector, 
			(unsigned long long)logical_sector);

4263
		sh = get_active_stripe(conf, new_sector, previous,
4264
				       (bi->bi_rw&RWA_MASK), 0);
L
Linus Torvalds 已提交
4265
		if (sh) {
4266
			if (unlikely(previous)) {
4267
				/* expansion might have moved on while waiting for a
4268 4269 4270 4271 4272 4273
				 * stripe, so we must do the range check again.
				 * Expansion could still move past after this
				 * test, but as we are holding a reference to
				 * 'sh', we know that if that happens,
				 *  STRIPE_EXPANDING will get set and the expansion
				 * won't proceed until we finish with the stripe.
4274 4275 4276
				 */
				int must_retry = 0;
				spin_lock_irq(&conf->device_lock);
4277
				if (mddev->reshape_backwards
4278 4279
				    ? logical_sector >= conf->reshape_progress
				    : logical_sector < conf->reshape_progress)
4280 4281 4282 4283 4284
					/* mismatch, need to try again */
					must_retry = 1;
				spin_unlock_irq(&conf->device_lock);
				if (must_retry) {
					release_stripe(sh);
4285
					schedule();
4286 4287 4288
					goto retry;
				}
			}
4289

4290
			if (rw == WRITE &&
4291
			    logical_sector >= mddev->suspend_lo &&
4292 4293
			    logical_sector < mddev->suspend_hi) {
				release_stripe(sh);
4294 4295 4296 4297 4298 4299 4300 4301 4302 4303
				/* As the suspend_* range is controlled by
				 * userspace, we want an interruptible
				 * wait.
				 */
				flush_signals(current);
				prepare_to_wait(&conf->wait_for_overlap,
						&w, TASK_INTERRUPTIBLE);
				if (logical_sector >= mddev->suspend_lo &&
				    logical_sector < mddev->suspend_hi)
					schedule();
4304 4305
				goto retry;
			}
4306 4307

			if (test_bit(STRIPE_EXPANDING, &sh->state) ||
4308
			    !add_stripe_bio(sh, bi, dd_idx, rw)) {
4309 4310
				/* Stripe is busy expanding or
				 * add failed due to overlap.  Flush everything
L
Linus Torvalds 已提交
4311 4312
				 * and wait a while
				 */
N
NeilBrown 已提交
4313
				md_wakeup_thread(mddev->thread);
L
Linus Torvalds 已提交
4314 4315 4316 4317 4318
				release_stripe(sh);
				schedule();
				goto retry;
			}
			finish_wait(&conf->wait_for_overlap, &w);
4319 4320
			set_bit(STRIPE_HANDLE, &sh->state);
			clear_bit(STRIPE_DELAYED, &sh->state);
4321
			if ((bi->bi_rw & REQ_SYNC) &&
4322 4323
			    !test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
				atomic_inc(&conf->preread_active_stripes);
4324
			release_stripe_plug(mddev, sh);
L
Linus Torvalds 已提交
4325 4326 4327 4328 4329 4330 4331
		} else {
			/* cannot get stripe for read-ahead, just give-up */
			clear_bit(BIO_UPTODATE, &bi->bi_flags);
			finish_wait(&conf->wait_for_overlap, &w);
			break;
		}
	}
4332

4333
	remaining = raid5_dec_bi_active_stripes(bi);
4334
	if (remaining == 0) {
L
Linus Torvalds 已提交
4335

4336
		if ( rw == WRITE )
L
Linus Torvalds 已提交
4337
			md_write_end(mddev);
4338

4339
		bio_endio(bi, 0);
L
Linus Torvalds 已提交
4340 4341 4342
	}
}

4343
static sector_t raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks);
D
Dan Williams 已提交
4344

4345
static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, int *skipped)
L
Linus Torvalds 已提交
4346
{
4347 4348 4349 4350 4351 4352 4353 4354 4355
	/* reshaping is quite different to recovery/resync so it is
	 * handled quite separately ... here.
	 *
	 * On each call to sync_request, we gather one chunk worth of
	 * destination stripes and flag them as expanding.
	 * Then we find all the source stripes and request reads.
	 * As the reads complete, handle_stripe will copy the data
	 * into the destination stripe and release that stripe.
	 */
4356
	struct r5conf *conf = mddev->private;
L
Linus Torvalds 已提交
4357
	struct stripe_head *sh;
4358
	sector_t first_sector, last_sector;
4359 4360 4361
	int raid_disks = conf->previous_raid_disks;
	int data_disks = raid_disks - conf->max_degraded;
	int new_data_disks = conf->raid_disks - conf->max_degraded;
4362 4363
	int i;
	int dd_idx;
4364
	sector_t writepos, readpos, safepos;
4365
	sector_t stripe_addr;
4366
	int reshape_sectors;
4367
	struct list_head stripes;
4368

4369 4370
	if (sector_nr == 0) {
		/* If restarting in the middle, skip the initial sectors */
4371
		if (mddev->reshape_backwards &&
4372 4373 4374
		    conf->reshape_progress < raid5_size(mddev, 0, 0)) {
			sector_nr = raid5_size(mddev, 0, 0)
				- conf->reshape_progress;
4375
		} else if (!mddev->reshape_backwards &&
4376 4377
			   conf->reshape_progress > 0)
			sector_nr = conf->reshape_progress;
4378
		sector_div(sector_nr, new_data_disks);
4379
		if (sector_nr) {
4380 4381
			mddev->curr_resync_completed = sector_nr;
			sysfs_notify(&mddev->kobj, NULL, "sync_completed");
4382 4383 4384
			*skipped = 1;
			return sector_nr;
		}
4385 4386
	}

4387 4388 4389 4390
	/* We need to process a full chunk at a time.
	 * If old and new chunk sizes differ, we need to process the
	 * largest of these
	 */
4391 4392
	if (mddev->new_chunk_sectors > mddev->chunk_sectors)
		reshape_sectors = mddev->new_chunk_sectors;
4393
	else
4394
		reshape_sectors = mddev->chunk_sectors;
4395

4396 4397 4398 4399 4400
	/* We update the metadata at least every 10 seconds, or when
	 * the data about to be copied would over-write the source of
	 * the data at the front of the range.  i.e. one new_stripe
	 * along from reshape_progress new_maps to after where
	 * reshape_safe old_maps to
4401
	 */
4402
	writepos = conf->reshape_progress;
4403
	sector_div(writepos, new_data_disks);
4404 4405
	readpos = conf->reshape_progress;
	sector_div(readpos, data_disks);
4406
	safepos = conf->reshape_safe;
4407
	sector_div(safepos, data_disks);
4408
	if (mddev->reshape_backwards) {
4409
		writepos -= min_t(sector_t, reshape_sectors, writepos);
4410
		readpos += reshape_sectors;
4411
		safepos += reshape_sectors;
4412
	} else {
4413
		writepos += reshape_sectors;
4414 4415
		readpos -= min_t(sector_t, reshape_sectors, readpos);
		safepos -= min_t(sector_t, reshape_sectors, safepos);
4416
	}
4417

4418 4419 4420 4421 4422 4423 4424 4425 4426 4427 4428 4429 4430 4431 4432
	/* Having calculated the 'writepos' possibly use it
	 * to set 'stripe_addr' which is where we will write to.
	 */
	if (mddev->reshape_backwards) {
		BUG_ON(conf->reshape_progress == 0);
		stripe_addr = writepos;
		BUG_ON((mddev->dev_sectors &
			~((sector_t)reshape_sectors - 1))
		       - reshape_sectors - stripe_addr
		       != sector_nr);
	} else {
		BUG_ON(writepos != sector_nr + reshape_sectors);
		stripe_addr = sector_nr;
	}

4433 4434 4435 4436
	/* 'writepos' is the most advanced device address we might write.
	 * 'readpos' is the least advanced device address we might read.
	 * 'safepos' is the least address recorded in the metadata as having
	 *     been reshaped.
4437 4438 4439 4440
	 * If there is a min_offset_diff, these are adjusted either by
	 * increasing the safepos/readpos if diff is negative, or
	 * increasing writepos if diff is positive.
	 * If 'readpos' is then behind 'writepos', there is no way that we can
4441 4442 4443 4444 4445 4446 4447 4448 4449 4450 4451 4452
	 * ensure safety in the face of a crash - that must be done by userspace
	 * making a backup of the data.  So in that case there is no particular
	 * rush to update metadata.
	 * Otherwise if 'safepos' is behind 'writepos', then we really need to
	 * update the metadata to advance 'safepos' to match 'readpos' so that
	 * we can be safe in the event of a crash.
	 * So we insist on updating metadata if safepos is behind writepos and
	 * readpos is beyond writepos.
	 * In any case, update the metadata every 10 seconds.
	 * Maybe that number should be configurable, but I'm not sure it is
	 * worth it.... maybe it could be a multiple of safemode_delay???
	 */
4453 4454 4455 4456 4457 4458
	if (conf->min_offset_diff < 0) {
		safepos += -conf->min_offset_diff;
		readpos += -conf->min_offset_diff;
	} else
		writepos += conf->min_offset_diff;

4459
	if ((mddev->reshape_backwards
4460 4461 4462
	     ? (safepos > writepos && readpos < writepos)
	     : (safepos < writepos && readpos > writepos)) ||
	    time_after(jiffies, conf->reshape_checkpoint + 10*HZ)) {
4463 4464 4465
		/* Cannot proceed until we've updated the superblock... */
		wait_event(conf->wait_for_overlap,
			   atomic_read(&conf->reshape_stripes)==0);
4466
		mddev->reshape_position = conf->reshape_progress;
4467
		mddev->curr_resync_completed = sector_nr;
4468
		conf->reshape_checkpoint = jiffies;
4469
		set_bit(MD_CHANGE_DEVS, &mddev->flags);
4470
		md_wakeup_thread(mddev->thread);
4471
		wait_event(mddev->sb_wait, mddev->flags == 0 ||
4472 4473
			   kthread_should_stop());
		spin_lock_irq(&conf->device_lock);
4474
		conf->reshape_safe = mddev->reshape_position;
4475 4476
		spin_unlock_irq(&conf->device_lock);
		wake_up(&conf->wait_for_overlap);
4477
		sysfs_notify(&mddev->kobj, NULL, "sync_completed");
4478 4479
	}

4480
	INIT_LIST_HEAD(&stripes);
4481
	for (i = 0; i < reshape_sectors; i += STRIPE_SECTORS) {
4482
		int j;
4483
		int skipped_disk = 0;
4484
		sh = get_active_stripe(conf, stripe_addr+i, 0, 0, 1);
4485 4486 4487 4488 4489 4490 4491 4492 4493
		set_bit(STRIPE_EXPANDING, &sh->state);
		atomic_inc(&conf->reshape_stripes);
		/* If any of this stripe is beyond the end of the old
		 * array, then we need to zero those blocks
		 */
		for (j=sh->disks; j--;) {
			sector_t s;
			if (j == sh->pd_idx)
				continue;
4494
			if (conf->level == 6 &&
4495
			    j == sh->qd_idx)
4496
				continue;
4497
			s = compute_blocknr(sh, j, 0);
D
Dan Williams 已提交
4498
			if (s < raid5_size(mddev, 0, 0)) {
4499
				skipped_disk = 1;
4500 4501 4502 4503 4504 4505
				continue;
			}
			memset(page_address(sh->dev[j].page), 0, STRIPE_SIZE);
			set_bit(R5_Expanded, &sh->dev[j].flags);
			set_bit(R5_UPTODATE, &sh->dev[j].flags);
		}
4506
		if (!skipped_disk) {
4507 4508 4509
			set_bit(STRIPE_EXPAND_READY, &sh->state);
			set_bit(STRIPE_HANDLE, &sh->state);
		}
4510
		list_add(&sh->lru, &stripes);
4511 4512
	}
	spin_lock_irq(&conf->device_lock);
4513
	if (mddev->reshape_backwards)
4514
		conf->reshape_progress -= reshape_sectors * new_data_disks;
4515
	else
4516
		conf->reshape_progress += reshape_sectors * new_data_disks;
4517 4518 4519 4520 4521 4522 4523
	spin_unlock_irq(&conf->device_lock);
	/* Ok, those stripe are ready. We can start scheduling
	 * reads on the source stripes.
	 * The source stripes are determined by mapping the first and last
	 * block on the destination stripes.
	 */
	first_sector =
4524
		raid5_compute_sector(conf, stripe_addr*(new_data_disks),
4525
				     1, &dd_idx, NULL);
4526
	last_sector =
4527
		raid5_compute_sector(conf, ((stripe_addr+reshape_sectors)
4528
					    * new_data_disks - 1),
4529
				     1, &dd_idx, NULL);
A
Andre Noll 已提交
4530 4531
	if (last_sector >= mddev->dev_sectors)
		last_sector = mddev->dev_sectors - 1;
4532
	while (first_sector <= last_sector) {
4533
		sh = get_active_stripe(conf, first_sector, 1, 0, 1);
4534 4535 4536 4537 4538
		set_bit(STRIPE_EXPAND_SOURCE, &sh->state);
		set_bit(STRIPE_HANDLE, &sh->state);
		release_stripe(sh);
		first_sector += STRIPE_SECTORS;
	}
4539 4540 4541 4542 4543 4544 4545 4546
	/* Now that the sources are clearly marked, we can release
	 * the destination stripes
	 */
	while (!list_empty(&stripes)) {
		sh = list_entry(stripes.next, struct stripe_head, lru);
		list_del_init(&sh->lru);
		release_stripe(sh);
	}
4547 4548 4549
	/* If this takes us to the resync_max point where we have to pause,
	 * then we need to write out the superblock.
	 */
4550
	sector_nr += reshape_sectors;
4551 4552
	if ((sector_nr - mddev->curr_resync_completed) * 2
	    >= mddev->resync_max - mddev->curr_resync_completed) {
4553 4554 4555
		/* Cannot proceed until we've updated the superblock... */
		wait_event(conf->wait_for_overlap,
			   atomic_read(&conf->reshape_stripes) == 0);
4556
		mddev->reshape_position = conf->reshape_progress;
4557
		mddev->curr_resync_completed = sector_nr;
4558
		conf->reshape_checkpoint = jiffies;
4559 4560 4561 4562 4563 4564
		set_bit(MD_CHANGE_DEVS, &mddev->flags);
		md_wakeup_thread(mddev->thread);
		wait_event(mddev->sb_wait,
			   !test_bit(MD_CHANGE_DEVS, &mddev->flags)
			   || kthread_should_stop());
		spin_lock_irq(&conf->device_lock);
4565
		conf->reshape_safe = mddev->reshape_position;
4566 4567
		spin_unlock_irq(&conf->device_lock);
		wake_up(&conf->wait_for_overlap);
4568
		sysfs_notify(&mddev->kobj, NULL, "sync_completed");
4569
	}
4570
	return reshape_sectors;
4571 4572 4573
}

/* FIXME go_faster isn't used */
4574
static inline sector_t sync_request(struct mddev *mddev, sector_t sector_nr, int *skipped, int go_faster)
4575
{
4576
	struct r5conf *conf = mddev->private;
4577
	struct stripe_head *sh;
A
Andre Noll 已提交
4578
	sector_t max_sector = mddev->dev_sectors;
N
NeilBrown 已提交
4579
	sector_t sync_blocks;
4580 4581
	int still_degraded = 0;
	int i;
L
Linus Torvalds 已提交
4582

4583
	if (sector_nr >= max_sector) {
L
Linus Torvalds 已提交
4584
		/* just being told to finish up .. nothing much to do */
4585

4586 4587 4588 4589
		if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
			end_reshape(conf);
			return 0;
		}
4590 4591 4592 4593

		if (mddev->curr_resync < max_sector) /* aborted */
			bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
					&sync_blocks, 1);
4594
		else /* completed sync */
4595 4596 4597
			conf->fullsync = 0;
		bitmap_close_sync(mddev->bitmap);

L
Linus Torvalds 已提交
4598 4599
		return 0;
	}
4600

4601 4602 4603
	/* Allow raid5_quiesce to complete */
	wait_event(conf->wait_for_overlap, conf->quiesce != 2);

4604 4605
	if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
		return reshape_request(mddev, sector_nr, skipped);
4606

4607 4608 4609 4610 4611 4612
	/* No need to check resync_max as we never do more than one
	 * stripe, and as resync_max will always be on a chunk boundary,
	 * if the check in md_do_sync didn't fire, there is no chance
	 * of overstepping resync_max here
	 */

4613
	/* if there is too many failed drives and we are trying
L
Linus Torvalds 已提交
4614 4615 4616
	 * to resync, then assert that we are finished, because there is
	 * nothing we can do.
	 */
4617
	if (mddev->degraded >= conf->max_degraded &&
4618
	    test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
A
Andre Noll 已提交
4619
		sector_t rv = mddev->dev_sectors - sector_nr;
4620
		*skipped = 1;
L
Linus Torvalds 已提交
4621 4622
		return rv;
	}
4623
	if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
4624
	    !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
4625 4626 4627 4628 4629 4630
	    !conf->fullsync && sync_blocks >= STRIPE_SECTORS) {
		/* we can skip this block, and probably more */
		sync_blocks /= STRIPE_SECTORS;
		*skipped = 1;
		return sync_blocks * STRIPE_SECTORS; /* keep things rounded to whole stripes */
	}
L
Linus Torvalds 已提交
4631

N
NeilBrown 已提交
4632 4633
	bitmap_cond_end_sync(mddev->bitmap, sector_nr);

4634
	sh = get_active_stripe(conf, sector_nr, 0, 1, 0);
L
Linus Torvalds 已提交
4635
	if (sh == NULL) {
4636
		sh = get_active_stripe(conf, sector_nr, 0, 0, 0);
L
Linus Torvalds 已提交
4637
		/* make sure we don't swamp the stripe cache if someone else
4638
		 * is trying to get access
L
Linus Torvalds 已提交
4639
		 */
4640
		schedule_timeout_uninterruptible(1);
L
Linus Torvalds 已提交
4641
	}
4642 4643 4644 4645
	/* Need to check if array will still be degraded after recovery/resync
	 * We don't need to check the 'failed' flag as when that gets set,
	 * recovery aborts.
	 */
4646
	for (i = 0; i < conf->raid_disks; i++)
4647 4648 4649 4650 4651
		if (conf->disks[i].rdev == NULL)
			still_degraded = 1;

	bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, still_degraded);

4652
	set_bit(STRIPE_SYNC_REQUESTED, &sh->state);
L
Linus Torvalds 已提交
4653

4654
	handle_stripe(sh);
L
Linus Torvalds 已提交
4655 4656 4657 4658 4659
	release_stripe(sh);

	return STRIPE_SECTORS;
}

4660
static int  retry_aligned_read(struct r5conf *conf, struct bio *raid_bio)
4661 4662 4663 4664 4665 4666 4667 4668 4669 4670 4671 4672
{
	/* We may not be able to submit a whole bio at once as there
	 * may not be enough stripe_heads available.
	 * We cannot pre-allocate enough stripe_heads as we may need
	 * more than exist in the cache (if we allow ever large chunks).
	 * So we do one stripe head at a time and record in
	 * ->bi_hw_segments how many have been done.
	 *
	 * We *know* that this entire raid_bio is in one chunk, so
	 * it will be only one 'dd_idx' and only need one call to raid5_compute_sector.
	 */
	struct stripe_head *sh;
4673
	int dd_idx;
4674 4675 4676 4677 4678 4679
	sector_t sector, logical_sector, last_sector;
	int scnt = 0;
	int remaining;
	int handled = 0;

	logical_sector = raid_bio->bi_sector & ~((sector_t)STRIPE_SECTORS-1);
4680
	sector = raid5_compute_sector(conf, logical_sector,
4681
				      0, &dd_idx, NULL);
K
Kent Overstreet 已提交
4682
	last_sector = bio_end_sector(raid_bio);
4683 4684

	for (; logical_sector < last_sector;
4685 4686 4687
	     logical_sector += STRIPE_SECTORS,
		     sector += STRIPE_SECTORS,
		     scnt++) {
4688

4689
		if (scnt < raid5_bi_processed_stripes(raid_bio))
4690 4691 4692
			/* already done this stripe */
			continue;

4693
		sh = get_active_stripe(conf, sector, 0, 1, 0);
4694 4695 4696

		if (!sh) {
			/* failed to get a stripe - must wait */
4697
			raid5_set_bi_processed_stripes(raid_bio, scnt);
4698 4699 4700 4701
			conf->retry_read_aligned = raid_bio;
			return handled;
		}

4702 4703
		if (!add_stripe_bio(sh, raid_bio, dd_idx, 0)) {
			release_stripe(sh);
4704
			raid5_set_bi_processed_stripes(raid_bio, scnt);
4705 4706 4707 4708
			conf->retry_read_aligned = raid_bio;
			return handled;
		}

4709
		set_bit(R5_ReadNoMerge, &sh->dev[dd_idx].flags);
4710
		handle_stripe(sh);
4711 4712 4713
		release_stripe(sh);
		handled++;
	}
4714
	remaining = raid5_dec_bi_active_stripes(raid_bio);
4715
	if (remaining == 0)
4716
		bio_endio(raid_bio, 0);
4717 4718 4719 4720 4721
	if (atomic_dec_and_test(&conf->active_aligned_reads))
		wake_up(&conf->wait_for_stripe);
	return handled;
}

4722 4723 4724 4725 4726 4727 4728 4729 4730 4731 4732 4733 4734 4735 4736 4737 4738 4739 4740 4741 4742 4743 4744 4745
#define MAX_STRIPE_BATCH 8
static int handle_active_stripes(struct r5conf *conf)
{
	struct stripe_head *batch[MAX_STRIPE_BATCH], *sh;
	int i, batch_size = 0;

	while (batch_size < MAX_STRIPE_BATCH &&
			(sh = __get_priority_stripe(conf)) != NULL)
		batch[batch_size++] = sh;

	if (batch_size == 0)
		return batch_size;
	spin_unlock_irq(&conf->device_lock);

	for (i = 0; i < batch_size; i++)
		handle_stripe(batch[i]);

	cond_resched();

	spin_lock_irq(&conf->device_lock);
	for (i = 0; i < batch_size; i++)
		__release_stripe(conf, batch[i]);
	return batch_size;
}
4746

L
Linus Torvalds 已提交
4747 4748 4749 4750 4751 4752 4753
/*
 * This is our raid5 kernel thread.
 *
 * We scan the hash table for stripes which can be handled now.
 * During the scan, completed stripes are saved for us by the interrupt
 * handler, so that they will not have to wait for our next wakeup.
 */
S
Shaohua Li 已提交
4754
static void raid5d(struct md_thread *thread)
L
Linus Torvalds 已提交
4755
{
S
Shaohua Li 已提交
4756
	struct mddev *mddev = thread->mddev;
4757
	struct r5conf *conf = mddev->private;
L
Linus Torvalds 已提交
4758
	int handled;
4759
	struct blk_plug plug;
L
Linus Torvalds 已提交
4760

4761
	pr_debug("+++ raid5d active\n");
L
Linus Torvalds 已提交
4762 4763 4764

	md_check_recovery(mddev);

4765
	blk_start_plug(&plug);
L
Linus Torvalds 已提交
4766 4767 4768
	handled = 0;
	spin_lock_irq(&conf->device_lock);
	while (1) {
4769
		struct bio *bio;
4770
		int batch_size;
L
Linus Torvalds 已提交
4771

4772
		if (
4773 4774 4775
		    !list_empty(&conf->bitmap_list)) {
			/* Now is a good time to flush some bitmap updates */
			conf->seq_flush++;
4776
			spin_unlock_irq(&conf->device_lock);
4777
			bitmap_unplug(mddev->bitmap);
4778
			spin_lock_irq(&conf->device_lock);
4779
			conf->seq_write = conf->seq_flush;
4780 4781
			activate_bit_delay(conf);
		}
4782
		raid5_activate_delayed(conf);
4783

4784 4785 4786 4787 4788 4789 4790 4791 4792 4793
		while ((bio = remove_bio_from_retry(conf))) {
			int ok;
			spin_unlock_irq(&conf->device_lock);
			ok = retry_aligned_read(conf, bio);
			spin_lock_irq(&conf->device_lock);
			if (!ok)
				break;
			handled++;
		}

4794 4795
		batch_size = handle_active_stripes(conf);
		if (!batch_size)
L
Linus Torvalds 已提交
4796
			break;
4797
		handled += batch_size;
L
Linus Torvalds 已提交
4798

4799 4800
		if (mddev->flags & ~(1<<MD_CHANGE_PENDING)) {
			spin_unlock_irq(&conf->device_lock);
4801
			md_check_recovery(mddev);
4802 4803
			spin_lock_irq(&conf->device_lock);
		}
L
Linus Torvalds 已提交
4804
	}
4805
	pr_debug("%d stripes handled\n", handled);
L
Linus Torvalds 已提交
4806 4807 4808

	spin_unlock_irq(&conf->device_lock);

4809
	async_tx_issue_pending_all();
4810
	blk_finish_plug(&plug);
L
Linus Torvalds 已提交
4811

4812
	pr_debug("--- raid5d inactive\n");
L
Linus Torvalds 已提交
4813 4814
}

4815
static ssize_t
4816
raid5_show_stripe_cache_size(struct mddev *mddev, char *page)
4817
{
4818
	struct r5conf *conf = mddev->private;
4819 4820 4821 4822
	if (conf)
		return sprintf(page, "%d\n", conf->max_nr_stripes);
	else
		return 0;
4823 4824
}

4825
int
4826
raid5_set_cache_size(struct mddev *mddev, int size)
4827
{
4828
	struct r5conf *conf = mddev->private;
4829 4830
	int err;

4831
	if (size <= 16 || size > 32768)
4832
		return -EINVAL;
4833
	while (size < conf->max_nr_stripes) {
4834 4835 4836 4837 4838
		if (drop_one_stripe(conf))
			conf->max_nr_stripes--;
		else
			break;
	}
4839 4840 4841
	err = md_allow_write(mddev);
	if (err)
		return err;
4842
	while (size > conf->max_nr_stripes) {
4843 4844 4845 4846
		if (grow_one_stripe(conf))
			conf->max_nr_stripes++;
		else break;
	}
4847 4848 4849 4850 4851
	return 0;
}
EXPORT_SYMBOL(raid5_set_cache_size);

static ssize_t
4852
raid5_store_stripe_cache_size(struct mddev *mddev, const char *page, size_t len)
4853
{
4854
	struct r5conf *conf = mddev->private;
4855 4856 4857 4858 4859 4860 4861 4862 4863 4864 4865 4866 4867
	unsigned long new;
	int err;

	if (len >= PAGE_SIZE)
		return -EINVAL;
	if (!conf)
		return -ENODEV;

	if (strict_strtoul(page, 10, &new))
		return -EINVAL;
	err = raid5_set_cache_size(mddev, new);
	if (err)
		return err;
4868 4869
	return len;
}
4870

4871 4872 4873 4874
static struct md_sysfs_entry
raid5_stripecache_size = __ATTR(stripe_cache_size, S_IRUGO | S_IWUSR,
				raid5_show_stripe_cache_size,
				raid5_store_stripe_cache_size);
4875

4876
static ssize_t
4877
raid5_show_preread_threshold(struct mddev *mddev, char *page)
4878
{
4879
	struct r5conf *conf = mddev->private;
4880 4881 4882 4883 4884 4885 4886
	if (conf)
		return sprintf(page, "%d\n", conf->bypass_threshold);
	else
		return 0;
}

static ssize_t
4887
raid5_store_preread_threshold(struct mddev *mddev, const char *page, size_t len)
4888
{
4889
	struct r5conf *conf = mddev->private;
4890
	unsigned long new;
4891 4892 4893 4894 4895
	if (len >= PAGE_SIZE)
		return -EINVAL;
	if (!conf)
		return -ENODEV;

4896
	if (strict_strtoul(page, 10, &new))
4897
		return -EINVAL;
4898
	if (new > conf->max_nr_stripes)
4899 4900 4901 4902 4903 4904 4905 4906 4907 4908 4909
		return -EINVAL;
	conf->bypass_threshold = new;
	return len;
}

static struct md_sysfs_entry
raid5_preread_bypass_threshold = __ATTR(preread_bypass_threshold,
					S_IRUGO | S_IWUSR,
					raid5_show_preread_threshold,
					raid5_store_preread_threshold);

4910
static ssize_t
4911
stripe_cache_active_show(struct mddev *mddev, char *page)
4912
{
4913
	struct r5conf *conf = mddev->private;
4914 4915 4916 4917
	if (conf)
		return sprintf(page, "%d\n", atomic_read(&conf->active_stripes));
	else
		return 0;
4918 4919
}

4920 4921
static struct md_sysfs_entry
raid5_stripecache_active = __ATTR_RO(stripe_cache_active);
4922

4923
static struct attribute *raid5_attrs[] =  {
4924 4925
	&raid5_stripecache_size.attr,
	&raid5_stripecache_active.attr,
4926
	&raid5_preread_bypass_threshold.attr,
4927 4928
	NULL,
};
4929 4930 4931
static struct attribute_group raid5_attrs_group = {
	.name = NULL,
	.attrs = raid5_attrs,
4932 4933
};

4934
static sector_t
4935
raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks)
4936
{
4937
	struct r5conf *conf = mddev->private;
4938 4939 4940

	if (!sectors)
		sectors = mddev->dev_sectors;
4941
	if (!raid_disks)
4942
		/* size is defined by the smallest of previous and new size */
4943
		raid_disks = min(conf->raid_disks, conf->previous_raid_disks);
4944

4945
	sectors &= ~((sector_t)mddev->chunk_sectors - 1);
4946
	sectors &= ~((sector_t)mddev->new_chunk_sectors - 1);
4947 4948 4949
	return sectors * (raid_disks - conf->max_degraded);
}

4950
static void raid5_free_percpu(struct r5conf *conf)
4951 4952 4953 4954 4955 4956 4957 4958 4959 4960 4961
{
	struct raid5_percpu *percpu;
	unsigned long cpu;

	if (!conf->percpu)
		return;

	get_online_cpus();
	for_each_possible_cpu(cpu) {
		percpu = per_cpu_ptr(conf->percpu, cpu);
		safe_put_page(percpu->spare_page);
4962
		kfree(percpu->scribble);
4963 4964 4965 4966 4967 4968 4969 4970 4971
	}
#ifdef CONFIG_HOTPLUG_CPU
	unregister_cpu_notifier(&conf->cpu_notify);
#endif
	put_online_cpus();

	free_percpu(conf->percpu);
}

4972
static void free_conf(struct r5conf *conf)
4973 4974
{
	shrink_stripes(conf);
4975
	raid5_free_percpu(conf);
4976 4977 4978 4979 4980
	kfree(conf->disks);
	kfree(conf->stripe_hashtbl);
	kfree(conf);
}

4981 4982 4983 4984
#ifdef CONFIG_HOTPLUG_CPU
static int raid456_cpu_notify(struct notifier_block *nfb, unsigned long action,
			      void *hcpu)
{
4985
	struct r5conf *conf = container_of(nfb, struct r5conf, cpu_notify);
4986 4987 4988 4989 4990 4991
	long cpu = (long)hcpu;
	struct raid5_percpu *percpu = per_cpu_ptr(conf->percpu, cpu);

	switch (action) {
	case CPU_UP_PREPARE:
	case CPU_UP_PREPARE_FROZEN:
4992
		if (conf->level == 6 && !percpu->spare_page)
4993
			percpu->spare_page = alloc_page(GFP_KERNEL);
4994 4995 4996 4997 4998 4999 5000
		if (!percpu->scribble)
			percpu->scribble = kmalloc(conf->scribble_len, GFP_KERNEL);

		if (!percpu->scribble ||
		    (conf->level == 6 && !percpu->spare_page)) {
			safe_put_page(percpu->spare_page);
			kfree(percpu->scribble);
5001 5002
			pr_err("%s: failed memory allocation for cpu%ld\n",
			       __func__, cpu);
5003
			return notifier_from_errno(-ENOMEM);
5004 5005 5006 5007 5008
		}
		break;
	case CPU_DEAD:
	case CPU_DEAD_FROZEN:
		safe_put_page(percpu->spare_page);
5009
		kfree(percpu->scribble);
5010
		percpu->spare_page = NULL;
5011
		percpu->scribble = NULL;
5012 5013 5014 5015 5016 5017 5018 5019
		break;
	default:
		break;
	}
	return NOTIFY_OK;
}
#endif

5020
static int raid5_alloc_percpu(struct r5conf *conf)
5021 5022 5023
{
	unsigned long cpu;
	struct page *spare_page;
5024
	struct raid5_percpu __percpu *allcpus;
5025
	void *scribble;
5026 5027 5028 5029 5030 5031 5032 5033 5034 5035
	int err;

	allcpus = alloc_percpu(struct raid5_percpu);
	if (!allcpus)
		return -ENOMEM;
	conf->percpu = allcpus;

	get_online_cpus();
	err = 0;
	for_each_present_cpu(cpu) {
5036 5037 5038 5039 5040 5041 5042 5043
		if (conf->level == 6) {
			spare_page = alloc_page(GFP_KERNEL);
			if (!spare_page) {
				err = -ENOMEM;
				break;
			}
			per_cpu_ptr(conf->percpu, cpu)->spare_page = spare_page;
		}
5044
		scribble = kmalloc(conf->scribble_len, GFP_KERNEL);
5045
		if (!scribble) {
5046 5047 5048
			err = -ENOMEM;
			break;
		}
5049
		per_cpu_ptr(conf->percpu, cpu)->scribble = scribble;
5050 5051 5052 5053 5054 5055 5056 5057 5058 5059 5060 5061
	}
#ifdef CONFIG_HOTPLUG_CPU
	conf->cpu_notify.notifier_call = raid456_cpu_notify;
	conf->cpu_notify.priority = 0;
	if (err == 0)
		err = register_cpu_notifier(&conf->cpu_notify);
#endif
	put_online_cpus();

	return err;
}

5062
static struct r5conf *setup_conf(struct mddev *mddev)
L
Linus Torvalds 已提交
5063
{
5064
	struct r5conf *conf;
5065
	int raid_disk, memory, max_disks;
5066
	struct md_rdev *rdev;
L
Linus Torvalds 已提交
5067
	struct disk_info *disk;
5068
	char pers_name[6];
L
Linus Torvalds 已提交
5069

N
NeilBrown 已提交
5070 5071 5072
	if (mddev->new_level != 5
	    && mddev->new_level != 4
	    && mddev->new_level != 6) {
5073
		printk(KERN_ERR "md/raid:%s: raid level not set to 4/5/6 (%d)\n",
N
NeilBrown 已提交
5074 5075
		       mdname(mddev), mddev->new_level);
		return ERR_PTR(-EIO);
L
Linus Torvalds 已提交
5076
	}
N
NeilBrown 已提交
5077 5078 5079 5080
	if ((mddev->new_level == 5
	     && !algorithm_valid_raid5(mddev->new_layout)) ||
	    (mddev->new_level == 6
	     && !algorithm_valid_raid6(mddev->new_layout))) {
5081
		printk(KERN_ERR "md/raid:%s: layout %d not supported\n",
N
NeilBrown 已提交
5082 5083
		       mdname(mddev), mddev->new_layout);
		return ERR_PTR(-EIO);
5084
	}
N
NeilBrown 已提交
5085
	if (mddev->new_level == 6 && mddev->raid_disks < 4) {
5086
		printk(KERN_ERR "md/raid:%s: not enough configured devices (%d, minimum 4)\n",
N
NeilBrown 已提交
5087 5088
		       mdname(mddev), mddev->raid_disks);
		return ERR_PTR(-EINVAL);
5089 5090
	}

5091 5092 5093
	if (!mddev->new_chunk_sectors ||
	    (mddev->new_chunk_sectors << 9) % PAGE_SIZE ||
	    !is_power_of_2(mddev->new_chunk_sectors)) {
5094 5095
		printk(KERN_ERR "md/raid:%s: invalid chunk size %d\n",
		       mdname(mddev), mddev->new_chunk_sectors << 9);
N
NeilBrown 已提交
5096
		return ERR_PTR(-EINVAL);
5097 5098
	}

5099
	conf = kzalloc(sizeof(struct r5conf), GFP_KERNEL);
N
NeilBrown 已提交
5100
	if (conf == NULL)
L
Linus Torvalds 已提交
5101
		goto abort;
5102 5103 5104 5105 5106 5107 5108 5109 5110 5111 5112 5113
	spin_lock_init(&conf->device_lock);
	init_waitqueue_head(&conf->wait_for_stripe);
	init_waitqueue_head(&conf->wait_for_overlap);
	INIT_LIST_HEAD(&conf->handle_list);
	INIT_LIST_HEAD(&conf->hold_list);
	INIT_LIST_HEAD(&conf->delayed_list);
	INIT_LIST_HEAD(&conf->bitmap_list);
	INIT_LIST_HEAD(&conf->inactive_list);
	atomic_set(&conf->active_stripes, 0);
	atomic_set(&conf->preread_active_stripes, 0);
	atomic_set(&conf->active_aligned_reads, 0);
	conf->bypass_threshold = BYPASS_THRESHOLD;
5114
	conf->recovery_disabled = mddev->recovery_disabled - 1;
N
NeilBrown 已提交
5115 5116 5117 5118 5119

	conf->raid_disks = mddev->raid_disks;
	if (mddev->reshape_position == MaxSector)
		conf->previous_raid_disks = mddev->raid_disks;
	else
5120
		conf->previous_raid_disks = mddev->raid_disks - mddev->delta_disks;
5121 5122
	max_disks = max(conf->raid_disks, conf->previous_raid_disks);
	conf->scribble_len = scribble_len(max_disks);
5123

5124
	conf->disks = kzalloc(max_disks * sizeof(struct disk_info),
5125 5126 5127
			      GFP_KERNEL);
	if (!conf->disks)
		goto abort;
5128

L
Linus Torvalds 已提交
5129 5130
	conf->mddev = mddev;

5131
	if ((conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL)) == NULL)
L
Linus Torvalds 已提交
5132 5133
		goto abort;

5134 5135 5136 5137
	conf->level = mddev->new_level;
	if (raid5_alloc_percpu(conf) != 0)
		goto abort;

5138
	pr_debug("raid456: run(%s) called.\n", mdname(mddev));
L
Linus Torvalds 已提交
5139

N
NeilBrown 已提交
5140
	rdev_for_each(rdev, mddev) {
L
Linus Torvalds 已提交
5141
		raid_disk = rdev->raid_disk;
5142
		if (raid_disk >= max_disks
L
Linus Torvalds 已提交
5143 5144 5145 5146
		    || raid_disk < 0)
			continue;
		disk = conf->disks + raid_disk;

5147 5148 5149 5150 5151 5152 5153 5154 5155
		if (test_bit(Replacement, &rdev->flags)) {
			if (disk->replacement)
				goto abort;
			disk->replacement = rdev;
		} else {
			if (disk->rdev)
				goto abort;
			disk->rdev = rdev;
		}
L
Linus Torvalds 已提交
5156

5157
		if (test_bit(In_sync, &rdev->flags)) {
L
Linus Torvalds 已提交
5158
			char b[BDEVNAME_SIZE];
5159 5160 5161
			printk(KERN_INFO "md/raid:%s: device %s operational as raid"
			       " disk %d\n",
			       mdname(mddev), bdevname(rdev->bdev, b), raid_disk);
J
Jonathan Brassow 已提交
5162
		} else if (rdev->saved_raid_disk != raid_disk)
5163 5164
			/* Cannot rely on bitmap to complete recovery */
			conf->fullsync = 1;
L
Linus Torvalds 已提交
5165 5166
	}

5167
	conf->chunk_sectors = mddev->new_chunk_sectors;
N
NeilBrown 已提交
5168
	conf->level = mddev->new_level;
5169 5170 5171 5172
	if (conf->level == 6)
		conf->max_degraded = 2;
	else
		conf->max_degraded = 1;
N
NeilBrown 已提交
5173
	conf->algorithm = mddev->new_layout;
L
Linus Torvalds 已提交
5174
	conf->max_nr_stripes = NR_STRIPES;
5175
	conf->reshape_progress = mddev->reshape_position;
5176
	if (conf->reshape_progress != MaxSector) {
5177
		conf->prev_chunk_sectors = mddev->chunk_sectors;
5178 5179
		conf->prev_algo = mddev->layout;
	}
L
Linus Torvalds 已提交
5180

N
NeilBrown 已提交
5181
	memory = conf->max_nr_stripes * (sizeof(struct stripe_head) +
5182
		 max_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
N
NeilBrown 已提交
5183 5184
	if (grow_stripes(conf, conf->max_nr_stripes)) {
		printk(KERN_ERR
5185 5186
		       "md/raid:%s: couldn't allocate %dkB for buffers\n",
		       mdname(mddev), memory);
N
NeilBrown 已提交
5187 5188
		goto abort;
	} else
5189 5190
		printk(KERN_INFO "md/raid:%s: allocated %dkB\n",
		       mdname(mddev), memory);
L
Linus Torvalds 已提交
5191

5192 5193
	sprintf(pers_name, "raid%d", mddev->new_level);
	conf->thread = md_register_thread(raid5d, mddev, pers_name);
N
NeilBrown 已提交
5194 5195
	if (!conf->thread) {
		printk(KERN_ERR
5196
		       "md/raid:%s: couldn't allocate thread.\n",
N
NeilBrown 已提交
5197
		       mdname(mddev));
5198 5199
		goto abort;
	}
N
NeilBrown 已提交
5200 5201 5202 5203 5204

	return conf;

 abort:
	if (conf) {
5205
		free_conf(conf);
N
NeilBrown 已提交
5206 5207 5208 5209 5210
		return ERR_PTR(-EIO);
	} else
		return ERR_PTR(-ENOMEM);
}

5211 5212 5213 5214 5215 5216 5217 5218 5219 5220 5221 5222 5223 5224 5225 5226 5227 5228 5229 5230 5231 5232 5233 5234 5235 5236 5237

static int only_parity(int raid_disk, int algo, int raid_disks, int max_degraded)
{
	switch (algo) {
	case ALGORITHM_PARITY_0:
		if (raid_disk < max_degraded)
			return 1;
		break;
	case ALGORITHM_PARITY_N:
		if (raid_disk >= raid_disks - max_degraded)
			return 1;
		break;
	case ALGORITHM_PARITY_0_6:
		if (raid_disk == 0 || 
		    raid_disk == raid_disks - 1)
			return 1;
		break;
	case ALGORITHM_LEFT_ASYMMETRIC_6:
	case ALGORITHM_RIGHT_ASYMMETRIC_6:
	case ALGORITHM_LEFT_SYMMETRIC_6:
	case ALGORITHM_RIGHT_SYMMETRIC_6:
		if (raid_disk == raid_disks - 1)
			return 1;
	}
	return 0;
}

5238
static int run(struct mddev *mddev)
N
NeilBrown 已提交
5239
{
5240
	struct r5conf *conf;
5241
	int working_disks = 0;
5242
	int dirty_parity_disks = 0;
5243
	struct md_rdev *rdev;
5244
	sector_t reshape_offset = 0;
5245
	int i;
5246 5247
	long long min_offset_diff = 0;
	int first = 1;
N
NeilBrown 已提交
5248

5249
	if (mddev->recovery_cp != MaxSector)
5250
		printk(KERN_NOTICE "md/raid:%s: not clean"
5251 5252
		       " -- starting background reconstruction\n",
		       mdname(mddev));
5253 5254 5255 5256 5257 5258 5259 5260 5261 5262 5263 5264 5265 5266 5267 5268 5269

	rdev_for_each(rdev, mddev) {
		long long diff;
		if (rdev->raid_disk < 0)
			continue;
		diff = (rdev->new_data_offset - rdev->data_offset);
		if (first) {
			min_offset_diff = diff;
			first = 0;
		} else if (mddev->reshape_backwards &&
			 diff < min_offset_diff)
			min_offset_diff = diff;
		else if (!mddev->reshape_backwards &&
			 diff > min_offset_diff)
			min_offset_diff = diff;
	}

N
NeilBrown 已提交
5270 5271
	if (mddev->reshape_position != MaxSector) {
		/* Check that we can continue the reshape.
5272 5273 5274 5275 5276 5277 5278 5279 5280 5281
		 * Difficulties arise if the stripe we would write to
		 * next is at or after the stripe we would read from next.
		 * For a reshape that changes the number of devices, this
		 * is only possible for a very short time, and mdadm makes
		 * sure that time appears to have past before assembling
		 * the array.  So we fail if that time hasn't passed.
		 * For a reshape that keeps the number of devices the same
		 * mdadm must be monitoring the reshape can keeping the
		 * critical areas read-only and backed up.  It will start
		 * the array in read-only mode, so we check for that.
N
NeilBrown 已提交
5282 5283 5284
		 */
		sector_t here_new, here_old;
		int old_disks;
5285
		int max_degraded = (mddev->level == 6 ? 2 : 1);
N
NeilBrown 已提交
5286

5287
		if (mddev->new_level != mddev->level) {
5288
			printk(KERN_ERR "md/raid:%s: unsupported reshape "
N
NeilBrown 已提交
5289 5290 5291 5292 5293 5294 5295 5296 5297 5298
			       "required - aborting.\n",
			       mdname(mddev));
			return -EINVAL;
		}
		old_disks = mddev->raid_disks - mddev->delta_disks;
		/* reshape_position must be on a new-stripe boundary, and one
		 * further up in new geometry must map after here in old
		 * geometry.
		 */
		here_new = mddev->reshape_position;
5299
		if (sector_div(here_new, mddev->new_chunk_sectors *
N
NeilBrown 已提交
5300
			       (mddev->raid_disks - max_degraded))) {
5301 5302
			printk(KERN_ERR "md/raid:%s: reshape_position not "
			       "on a stripe boundary\n", mdname(mddev));
N
NeilBrown 已提交
5303 5304
			return -EINVAL;
		}
5305
		reshape_offset = here_new * mddev->new_chunk_sectors;
N
NeilBrown 已提交
5306 5307
		/* here_new is the stripe we will write to */
		here_old = mddev->reshape_position;
5308
		sector_div(here_old, mddev->chunk_sectors *
N
NeilBrown 已提交
5309 5310 5311
			   (old_disks-max_degraded));
		/* here_old is the first stripe that we might need to read
		 * from */
5312
		if (mddev->delta_disks == 0) {
5313 5314 5315 5316 5317 5318
			if ((here_new * mddev->new_chunk_sectors !=
			     here_old * mddev->chunk_sectors)) {
				printk(KERN_ERR "md/raid:%s: reshape position is"
				       " confused - aborting\n", mdname(mddev));
				return -EINVAL;
			}
5319
			/* We cannot be sure it is safe to start an in-place
5320
			 * reshape.  It is only safe if user-space is monitoring
5321 5322 5323 5324 5325
			 * and taking constant backups.
			 * mdadm always starts a situation like this in
			 * readonly mode so it can take control before
			 * allowing any writes.  So just check for that.
			 */
5326 5327 5328 5329 5330 5331 5332
			if (abs(min_offset_diff) >= mddev->chunk_sectors &&
			    abs(min_offset_diff) >= mddev->new_chunk_sectors)
				/* not really in-place - so OK */;
			else if (mddev->ro == 0) {
				printk(KERN_ERR "md/raid:%s: in-place reshape "
				       "must be started in read-only mode "
				       "- aborting\n",
5333
				       mdname(mddev));
5334 5335
				return -EINVAL;
			}
5336
		} else if (mddev->reshape_backwards
5337
		    ? (here_new * mddev->new_chunk_sectors + min_offset_diff <=
5338 5339
		       here_old * mddev->chunk_sectors)
		    : (here_new * mddev->new_chunk_sectors >=
5340
		       here_old * mddev->chunk_sectors + (-min_offset_diff))) {
N
NeilBrown 已提交
5341
			/* Reading from the same stripe as writing to - bad */
5342 5343 5344
			printk(KERN_ERR "md/raid:%s: reshape_position too early for "
			       "auto-recovery - aborting.\n",
			       mdname(mddev));
N
NeilBrown 已提交
5345 5346
			return -EINVAL;
		}
5347 5348
		printk(KERN_INFO "md/raid:%s: reshape will continue\n",
		       mdname(mddev));
N
NeilBrown 已提交
5349 5350 5351 5352
		/* OK, we should be able to continue; */
	} else {
		BUG_ON(mddev->level != mddev->new_level);
		BUG_ON(mddev->layout != mddev->new_layout);
5353
		BUG_ON(mddev->chunk_sectors != mddev->new_chunk_sectors);
N
NeilBrown 已提交
5354
		BUG_ON(mddev->delta_disks != 0);
L
Linus Torvalds 已提交
5355
	}
N
NeilBrown 已提交
5356

5357 5358 5359 5360 5361
	if (mddev->private == NULL)
		conf = setup_conf(mddev);
	else
		conf = mddev->private;

N
NeilBrown 已提交
5362 5363 5364
	if (IS_ERR(conf))
		return PTR_ERR(conf);

5365
	conf->min_offset_diff = min_offset_diff;
N
NeilBrown 已提交
5366 5367 5368 5369
	mddev->thread = conf->thread;
	conf->thread = NULL;
	mddev->private = conf;

5370 5371 5372 5373 5374 5375 5376 5377 5378 5379 5380
	for (i = 0; i < conf->raid_disks && conf->previous_raid_disks;
	     i++) {
		rdev = conf->disks[i].rdev;
		if (!rdev && conf->disks[i].replacement) {
			/* The replacement is all we have yet */
			rdev = conf->disks[i].replacement;
			conf->disks[i].replacement = NULL;
			clear_bit(Replacement, &rdev->flags);
			conf->disks[i].rdev = rdev;
		}
		if (!rdev)
5381
			continue;
5382 5383 5384 5385 5386 5387 5388
		if (conf->disks[i].replacement &&
		    conf->reshape_progress != MaxSector) {
			/* replacements and reshape simply do not mix. */
			printk(KERN_ERR "md: cannot handle concurrent "
			       "replacement and reshape.\n");
			goto abort;
		}
5389
		if (test_bit(In_sync, &rdev->flags)) {
N
NeilBrown 已提交
5390
			working_disks++;
5391 5392
			continue;
		}
5393 5394 5395 5396 5397 5398 5399 5400 5401 5402 5403 5404 5405 5406 5407 5408 5409 5410 5411 5412 5413 5414 5415 5416 5417 5418 5419 5420
		/* This disc is not fully in-sync.  However if it
		 * just stored parity (beyond the recovery_offset),
		 * when we don't need to be concerned about the
		 * array being dirty.
		 * When reshape goes 'backwards', we never have
		 * partially completed devices, so we only need
		 * to worry about reshape going forwards.
		 */
		/* Hack because v0.91 doesn't store recovery_offset properly. */
		if (mddev->major_version == 0 &&
		    mddev->minor_version > 90)
			rdev->recovery_offset = reshape_offset;
			
		if (rdev->recovery_offset < reshape_offset) {
			/* We need to check old and new layout */
			if (!only_parity(rdev->raid_disk,
					 conf->algorithm,
					 conf->raid_disks,
					 conf->max_degraded))
				continue;
		}
		if (!only_parity(rdev->raid_disk,
				 conf->prev_algo,
				 conf->previous_raid_disks,
				 conf->max_degraded))
			continue;
		dirty_parity_disks++;
	}
N
NeilBrown 已提交
5421

5422 5423 5424
	/*
	 * 0 for a fully functional array, 1 or 2 for a degraded array.
	 */
5425
	mddev->degraded = calc_degraded(conf);
N
NeilBrown 已提交
5426

5427
	if (has_failed(conf)) {
5428
		printk(KERN_ERR "md/raid:%s: not enough operational devices"
L
Linus Torvalds 已提交
5429
			" (%d/%d failed)\n",
5430
			mdname(mddev), mddev->degraded, conf->raid_disks);
L
Linus Torvalds 已提交
5431 5432 5433
		goto abort;
	}

N
NeilBrown 已提交
5434
	/* device size must be a multiple of chunk size */
5435
	mddev->dev_sectors &= ~(mddev->chunk_sectors - 1);
N
NeilBrown 已提交
5436 5437
	mddev->resync_max_sectors = mddev->dev_sectors;

5438
	if (mddev->degraded > dirty_parity_disks &&
L
Linus Torvalds 已提交
5439
	    mddev->recovery_cp != MaxSector) {
5440 5441
		if (mddev->ok_start_degraded)
			printk(KERN_WARNING
5442 5443
			       "md/raid:%s: starting dirty degraded array"
			       " - data corruption possible.\n",
5444 5445 5446
			       mdname(mddev));
		else {
			printk(KERN_ERR
5447
			       "md/raid:%s: cannot start dirty degraded array.\n",
5448 5449 5450
			       mdname(mddev));
			goto abort;
		}
L
Linus Torvalds 已提交
5451 5452 5453
	}

	if (mddev->degraded == 0)
5454 5455
		printk(KERN_INFO "md/raid:%s: raid level %d active with %d out of %d"
		       " devices, algorithm %d\n", mdname(mddev), conf->level,
5456 5457
		       mddev->raid_disks-mddev->degraded, mddev->raid_disks,
		       mddev->new_layout);
L
Linus Torvalds 已提交
5458
	else
5459 5460 5461 5462 5463
		printk(KERN_ALERT "md/raid:%s: raid level %d active with %d"
		       " out of %d devices, algorithm %d\n",
		       mdname(mddev), conf->level,
		       mddev->raid_disks - mddev->degraded,
		       mddev->raid_disks, mddev->new_layout);
L
Linus Torvalds 已提交
5464 5465 5466

	print_raid5_conf(conf);

5467 5468
	if (conf->reshape_progress != MaxSector) {
		conf->reshape_safe = conf->reshape_progress;
5469 5470 5471 5472 5473 5474
		atomic_set(&conf->reshape_stripes, 0);
		clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
		clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
		set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
		set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
		mddev->sync_thread = md_register_thread(md_do_sync, mddev,
5475
							"reshape");
5476 5477
	}

L
Linus Torvalds 已提交
5478 5479

	/* Ok, everything is just fine now */
5480 5481
	if (mddev->to_remove == &raid5_attrs_group)
		mddev->to_remove = NULL;
N
NeilBrown 已提交
5482 5483
	else if (mddev->kobj.sd &&
	    sysfs_create_group(&mddev->kobj, &raid5_attrs_group))
5484
		printk(KERN_WARNING
5485
		       "raid5: failed to create sysfs attributes for %s\n",
5486
		       mdname(mddev));
5487
	md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
5488

5489
	if (mddev->queue) {
5490
		int chunk_size;
S
Shaohua Li 已提交
5491
		bool discard_supported = true;
5492 5493 5494 5495 5496 5497 5498 5499 5500
		/* read-ahead size must cover two whole stripes, which
		 * is 2 * (datadisks) * chunksize where 'n' is the
		 * number of raid devices
		 */
		int data_disks = conf->previous_raid_disks - conf->max_degraded;
		int stripe = data_disks *
			((mddev->chunk_sectors << 9) / PAGE_SIZE);
		if (mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
			mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
N
NeilBrown 已提交
5501

5502
		blk_queue_merge_bvec(mddev->queue, raid5_mergeable_bvec);
5503

N
NeilBrown 已提交
5504 5505
		mddev->queue->backing_dev_info.congested_data = mddev;
		mddev->queue->backing_dev_info.congested_fn = raid5_congested;
5506

5507 5508 5509 5510
		chunk_size = mddev->chunk_sectors << 9;
		blk_queue_io_min(mddev->queue, chunk_size);
		blk_queue_io_opt(mddev->queue, chunk_size *
				 (conf->raid_disks - conf->max_degraded));
S
Shaohua Li 已提交
5511 5512 5513 5514 5515
		/*
		 * We can only discard a whole stripe. It doesn't make sense to
		 * discard data disk but write parity disk
		 */
		stripe = stripe * PAGE_SIZE;
5516 5517 5518 5519
		/* Round up to power of 2, as discard handling
		 * currently assumes that */
		while ((stripe-1) & stripe)
			stripe = (stripe | (stripe-1)) + 1;
S
Shaohua Li 已提交
5520 5521 5522 5523 5524 5525 5526
		mddev->queue->limits.discard_alignment = stripe;
		mddev->queue->limits.discard_granularity = stripe;
		/*
		 * unaligned part of discard request will be ignored, so can't
		 * guarantee discard_zerors_data
		 */
		mddev->queue->limits.discard_zeroes_data = 0;
5527

5528
		rdev_for_each(rdev, mddev) {
5529 5530
			disk_stack_limits(mddev->gendisk, rdev->bdev,
					  rdev->data_offset << 9);
5531 5532
			disk_stack_limits(mddev->gendisk, rdev->bdev,
					  rdev->new_data_offset << 9);
S
Shaohua Li 已提交
5533 5534 5535 5536 5537 5538 5539 5540 5541 5542 5543 5544 5545 5546
			/*
			 * discard_zeroes_data is required, otherwise data
			 * could be lost. Consider a scenario: discard a stripe
			 * (the stripe could be inconsistent if
			 * discard_zeroes_data is 0); write one disk of the
			 * stripe (the stripe could be inconsistent again
			 * depending on which disks are used to calculate
			 * parity); the disk is broken; The stripe data of this
			 * disk is lost.
			 */
			if (!blk_queue_discard(bdev_get_queue(rdev->bdev)) ||
			    !bdev_get_queue(rdev->bdev)->
						limits.discard_zeroes_data)
				discard_supported = false;
5547
		}
S
Shaohua Li 已提交
5548 5549 5550 5551 5552 5553 5554 5555 5556

		if (discard_supported &&
		   mddev->queue->limits.max_discard_sectors >= stripe &&
		   mddev->queue->limits.discard_granularity >= stripe)
			queue_flag_set_unlocked(QUEUE_FLAG_DISCARD,
						mddev->queue);
		else
			queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD,
						mddev->queue);
5557
	}
5558

L
Linus Torvalds 已提交
5559 5560
	return 0;
abort:
5561
	md_unregister_thread(&mddev->thread);
N
NeilBrown 已提交
5562 5563
	print_raid5_conf(conf);
	free_conf(conf);
L
Linus Torvalds 已提交
5564
	mddev->private = NULL;
5565
	printk(KERN_ALERT "md/raid:%s: failed to run raid set.\n", mdname(mddev));
L
Linus Torvalds 已提交
5566 5567 5568
	return -EIO;
}

5569
static int stop(struct mddev *mddev)
L
Linus Torvalds 已提交
5570
{
5571
	struct r5conf *conf = mddev->private;
L
Linus Torvalds 已提交
5572

5573
	md_unregister_thread(&mddev->thread);
N
NeilBrown 已提交
5574 5575
	if (mddev->queue)
		mddev->queue->backing_dev_info.congested_fn = NULL;
5576
	free_conf(conf);
5577 5578
	mddev->private = NULL;
	mddev->to_remove = &raid5_attrs_group;
L
Linus Torvalds 已提交
5579 5580 5581
	return 0;
}

5582
static void status(struct seq_file *seq, struct mddev *mddev)
L
Linus Torvalds 已提交
5583
{
5584
	struct r5conf *conf = mddev->private;
L
Linus Torvalds 已提交
5585 5586
	int i;

5587 5588
	seq_printf(seq, " level %d, %dk chunk, algorithm %d", mddev->level,
		mddev->chunk_sectors / 2, mddev->layout);
5589
	seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->raid_disks - mddev->degraded);
L
Linus Torvalds 已提交
5590 5591 5592
	for (i = 0; i < conf->raid_disks; i++)
		seq_printf (seq, "%s",
			       conf->disks[i].rdev &&
5593
			       test_bit(In_sync, &conf->disks[i].rdev->flags) ? "U" : "_");
L
Linus Torvalds 已提交
5594 5595 5596
	seq_printf (seq, "]");
}

5597
static void print_raid5_conf (struct r5conf *conf)
L
Linus Torvalds 已提交
5598 5599 5600 5601
{
	int i;
	struct disk_info *tmp;

5602
	printk(KERN_DEBUG "RAID conf printout:\n");
L
Linus Torvalds 已提交
5603 5604 5605 5606
	if (!conf) {
		printk("(conf==NULL)\n");
		return;
	}
5607 5608 5609
	printk(KERN_DEBUG " --- level:%d rd:%d wd:%d\n", conf->level,
	       conf->raid_disks,
	       conf->raid_disks - conf->mddev->degraded);
L
Linus Torvalds 已提交
5610 5611 5612 5613 5614

	for (i = 0; i < conf->raid_disks; i++) {
		char b[BDEVNAME_SIZE];
		tmp = conf->disks + i;
		if (tmp->rdev)
5615 5616 5617
			printk(KERN_DEBUG " disk %d, o:%d, dev:%s\n",
			       i, !test_bit(Faulty, &tmp->rdev->flags),
			       bdevname(tmp->rdev->bdev, b));
L
Linus Torvalds 已提交
5618 5619 5620
	}
}

5621
static int raid5_spare_active(struct mddev *mddev)
L
Linus Torvalds 已提交
5622 5623
{
	int i;
5624
	struct r5conf *conf = mddev->private;
L
Linus Torvalds 已提交
5625
	struct disk_info *tmp;
5626 5627
	int count = 0;
	unsigned long flags;
L
Linus Torvalds 已提交
5628 5629 5630

	for (i = 0; i < conf->raid_disks; i++) {
		tmp = conf->disks + i;
5631 5632 5633 5634 5635 5636 5637 5638 5639 5640 5641 5642 5643 5644 5645 5646 5647 5648 5649
		if (tmp->replacement
		    && tmp->replacement->recovery_offset == MaxSector
		    && !test_bit(Faulty, &tmp->replacement->flags)
		    && !test_and_set_bit(In_sync, &tmp->replacement->flags)) {
			/* Replacement has just become active. */
			if (!tmp->rdev
			    || !test_and_clear_bit(In_sync, &tmp->rdev->flags))
				count++;
			if (tmp->rdev) {
				/* Replaced device not technically faulty,
				 * but we need to be sure it gets removed
				 * and never re-added.
				 */
				set_bit(Faulty, &tmp->rdev->flags);
				sysfs_notify_dirent_safe(
					tmp->rdev->sysfs_state);
			}
			sysfs_notify_dirent_safe(tmp->replacement->sysfs_state);
		} else if (tmp->rdev
5650
		    && tmp->rdev->recovery_offset == MaxSector
5651
		    && !test_bit(Faulty, &tmp->rdev->flags)
5652
		    && !test_and_set_bit(In_sync, &tmp->rdev->flags)) {
5653
			count++;
5654
			sysfs_notify_dirent_safe(tmp->rdev->sysfs_state);
L
Linus Torvalds 已提交
5655 5656
		}
	}
5657
	spin_lock_irqsave(&conf->device_lock, flags);
5658
	mddev->degraded = calc_degraded(conf);
5659
	spin_unlock_irqrestore(&conf->device_lock, flags);
L
Linus Torvalds 已提交
5660
	print_raid5_conf(conf);
5661
	return count;
L
Linus Torvalds 已提交
5662 5663
}

5664
static int raid5_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
L
Linus Torvalds 已提交
5665
{
5666
	struct r5conf *conf = mddev->private;
L
Linus Torvalds 已提交
5667
	int err = 0;
5668
	int number = rdev->raid_disk;
5669
	struct md_rdev **rdevp;
L
Linus Torvalds 已提交
5670 5671 5672
	struct disk_info *p = conf->disks + number;

	print_raid5_conf(conf);
5673 5674 5675 5676 5677 5678 5679 5680 5681 5682 5683 5684 5685 5686 5687 5688 5689 5690 5691 5692 5693 5694
	if (rdev == p->rdev)
		rdevp = &p->rdev;
	else if (rdev == p->replacement)
		rdevp = &p->replacement;
	else
		return 0;

	if (number >= conf->raid_disks &&
	    conf->reshape_progress == MaxSector)
		clear_bit(In_sync, &rdev->flags);

	if (test_bit(In_sync, &rdev->flags) ||
	    atomic_read(&rdev->nr_pending)) {
		err = -EBUSY;
		goto abort;
	}
	/* Only remove non-faulty devices if recovery
	 * isn't possible.
	 */
	if (!test_bit(Faulty, &rdev->flags) &&
	    mddev->recovery_disabled != conf->recovery_disabled &&
	    !has_failed(conf) &&
5695
	    (!p->replacement || p->replacement == rdev) &&
5696 5697 5698 5699 5700 5701 5702 5703 5704 5705
	    number < conf->raid_disks) {
		err = -EBUSY;
		goto abort;
	}
	*rdevp = NULL;
	synchronize_rcu();
	if (atomic_read(&rdev->nr_pending)) {
		/* lost the race, try later */
		err = -EBUSY;
		*rdevp = rdev;
5706 5707 5708 5709 5710 5711 5712 5713 5714 5715 5716 5717 5718 5719
	} else if (p->replacement) {
		/* We must have just cleared 'rdev' */
		p->rdev = p->replacement;
		clear_bit(Replacement, &p->replacement->flags);
		smp_mb(); /* Make sure other CPUs may see both as identical
			   * but will never see neither - if they are careful
			   */
		p->replacement = NULL;
		clear_bit(WantReplacement, &rdev->flags);
	} else
		/* We might have just removed the Replacement as faulty-
		 * clear the bit just in case
		 */
		clear_bit(WantReplacement, &rdev->flags);
L
Linus Torvalds 已提交
5720 5721 5722 5723 5724 5725
abort:

	print_raid5_conf(conf);
	return err;
}

5726
static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev)
L
Linus Torvalds 已提交
5727
{
5728
	struct r5conf *conf = mddev->private;
5729
	int err = -EEXIST;
L
Linus Torvalds 已提交
5730 5731
	int disk;
	struct disk_info *p;
5732 5733
	int first = 0;
	int last = conf->raid_disks - 1;
L
Linus Torvalds 已提交
5734

5735 5736 5737
	if (mddev->recovery_disabled == conf->recovery_disabled)
		return -EBUSY;

N
NeilBrown 已提交
5738
	if (rdev->saved_raid_disk < 0 && has_failed(conf))
L
Linus Torvalds 已提交
5739
		/* no point adding a device */
5740
		return -EINVAL;
L
Linus Torvalds 已提交
5741

5742 5743
	if (rdev->raid_disk >= 0)
		first = last = rdev->raid_disk;
L
Linus Torvalds 已提交
5744 5745

	/*
5746 5747
	 * find the disk ... but prefer rdev->saved_raid_disk
	 * if possible.
L
Linus Torvalds 已提交
5748
	 */
5749
	if (rdev->saved_raid_disk >= 0 &&
5750
	    rdev->saved_raid_disk >= first &&
5751
	    conf->disks[rdev->saved_raid_disk].rdev == NULL)
5752 5753 5754
		first = rdev->saved_raid_disk;

	for (disk = first; disk <= last; disk++) {
5755 5756
		p = conf->disks + disk;
		if (p->rdev == NULL) {
5757
			clear_bit(In_sync, &rdev->flags);
L
Linus Torvalds 已提交
5758
			rdev->raid_disk = disk;
5759
			err = 0;
5760 5761
			if (rdev->saved_raid_disk != disk)
				conf->fullsync = 1;
5762
			rcu_assign_pointer(p->rdev, rdev);
5763
			goto out;
L
Linus Torvalds 已提交
5764
		}
5765 5766 5767
	}
	for (disk = first; disk <= last; disk++) {
		p = conf->disks + disk;
5768 5769 5770 5771 5772 5773 5774 5775 5776 5777 5778
		if (test_bit(WantReplacement, &p->rdev->flags) &&
		    p->replacement == NULL) {
			clear_bit(In_sync, &rdev->flags);
			set_bit(Replacement, &rdev->flags);
			rdev->raid_disk = disk;
			err = 0;
			conf->fullsync = 1;
			rcu_assign_pointer(p->replacement, rdev);
			break;
		}
	}
5779
out:
L
Linus Torvalds 已提交
5780
	print_raid5_conf(conf);
5781
	return err;
L
Linus Torvalds 已提交
5782 5783
}

5784
static int raid5_resize(struct mddev *mddev, sector_t sectors)
L
Linus Torvalds 已提交
5785 5786 5787 5788 5789 5790 5791 5792
{
	/* no resync is happening, and there is enough space
	 * on all devices, so we can resize.
	 * We need to make sure resync covers any new space.
	 * If the array is shrinking we should possibly wait until
	 * any io in the removed space completes, but it hardly seems
	 * worth it.
	 */
5793
	sector_t newsize;
5794
	sectors &= ~((sector_t)mddev->chunk_sectors - 1);
5795 5796 5797
	newsize = raid5_size(mddev, sectors, mddev->raid_disks);
	if (mddev->external_size &&
	    mddev->array_sectors > newsize)
D
Dan Williams 已提交
5798
		return -EINVAL;
5799 5800 5801 5802 5803 5804
	if (mddev->bitmap) {
		int ret = bitmap_resize(mddev->bitmap, sectors, 0, 0);
		if (ret)
			return ret;
	}
	md_set_array_sectors(mddev, newsize);
5805
	set_capacity(mddev->gendisk, mddev->array_sectors);
5806
	revalidate_disk(mddev->gendisk);
5807 5808
	if (sectors > mddev->dev_sectors &&
	    mddev->recovery_cp > mddev->dev_sectors) {
A
Andre Noll 已提交
5809
		mddev->recovery_cp = mddev->dev_sectors;
L
Linus Torvalds 已提交
5810 5811
		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
	}
A
Andre Noll 已提交
5812
	mddev->dev_sectors = sectors;
5813
	mddev->resync_max_sectors = sectors;
L
Linus Torvalds 已提交
5814 5815 5816
	return 0;
}

5817
static int check_stripe_cache(struct mddev *mddev)
5818 5819 5820 5821 5822 5823 5824 5825 5826
{
	/* Can only proceed if there are plenty of stripe_heads.
	 * We need a minimum of one full stripe,, and for sensible progress
	 * it is best to have about 4 times that.
	 * If we require 4 times, then the default 256 4K stripe_heads will
	 * allow for chunk sizes up to 256K, which is probably OK.
	 * If the chunk size is greater, user-space should request more
	 * stripe_heads first.
	 */
5827
	struct r5conf *conf = mddev->private;
5828 5829 5830 5831
	if (((mddev->chunk_sectors << 9) / STRIPE_SIZE) * 4
	    > conf->max_nr_stripes ||
	    ((mddev->new_chunk_sectors << 9) / STRIPE_SIZE) * 4
	    > conf->max_nr_stripes) {
5832 5833
		printk(KERN_WARNING "md/raid:%s: reshape: not enough stripes.  Needed %lu\n",
		       mdname(mddev),
5834 5835 5836 5837 5838 5839 5840
		       ((max(mddev->chunk_sectors, mddev->new_chunk_sectors) << 9)
			/ STRIPE_SIZE)*4);
		return 0;
	}
	return 1;
}

5841
static int check_reshape(struct mddev *mddev)
5842
{
5843
	struct r5conf *conf = mddev->private;
5844

5845 5846
	if (mddev->delta_disks == 0 &&
	    mddev->new_layout == mddev->layout &&
5847
	    mddev->new_chunk_sectors == mddev->chunk_sectors)
5848
		return 0; /* nothing to do */
5849
	if (has_failed(conf))
5850 5851 5852 5853 5854 5855 5856 5857 5858 5859 5860 5861 5862
		return -EINVAL;
	if (mddev->delta_disks < 0) {
		/* We might be able to shrink, but the devices must
		 * be made bigger first.
		 * For raid6, 4 is the minimum size.
		 * Otherwise 2 is the minimum
		 */
		int min = 2;
		if (mddev->level == 6)
			min = 4;
		if (mddev->raid_disks + mddev->delta_disks < min)
			return -EINVAL;
	}
5863

5864
	if (!check_stripe_cache(mddev))
5865 5866
		return -ENOSPC;

5867 5868
	return resize_stripes(conf, (conf->previous_raid_disks
				     + mddev->delta_disks));
5869 5870
}

5871
static int raid5_start_reshape(struct mddev *mddev)
5872
{
5873
	struct r5conf *conf = mddev->private;
5874
	struct md_rdev *rdev;
5875
	int spares = 0;
5876
	unsigned long flags;
5877

5878
	if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
5879 5880
		return -EBUSY;

5881 5882 5883
	if (!check_stripe_cache(mddev))
		return -ENOSPC;

5884 5885 5886
	if (has_failed(conf))
		return -EINVAL;

5887
	rdev_for_each(rdev, mddev) {
5888 5889
		if (!test_bit(In_sync, &rdev->flags)
		    && !test_bit(Faulty, &rdev->flags))
5890
			spares++;
5891
	}
5892

5893
	if (spares - mddev->degraded < mddev->delta_disks - conf->max_degraded)
5894 5895 5896 5897 5898
		/* Not enough devices even to make a degraded array
		 * of that size
		 */
		return -EINVAL;

5899 5900 5901 5902 5903 5904
	/* Refuse to reduce size of the array.  Any reductions in
	 * array size must be through explicit setting of array_size
	 * attribute.
	 */
	if (raid5_size(mddev, 0, conf->raid_disks + mddev->delta_disks)
	    < mddev->array_sectors) {
5905
		printk(KERN_ERR "md/raid:%s: array size must be reduced "
5906 5907 5908 5909
		       "before number of disks\n", mdname(mddev));
		return -EINVAL;
	}

5910
	atomic_set(&conf->reshape_stripes, 0);
5911 5912
	spin_lock_irq(&conf->device_lock);
	conf->previous_raid_disks = conf->raid_disks;
5913
	conf->raid_disks += mddev->delta_disks;
5914 5915
	conf->prev_chunk_sectors = conf->chunk_sectors;
	conf->chunk_sectors = mddev->new_chunk_sectors;
5916 5917
	conf->prev_algo = conf->algorithm;
	conf->algorithm = mddev->new_layout;
5918 5919 5920 5921 5922
	conf->generation++;
	/* Code that selects data_offset needs to see the generation update
	 * if reshape_progress has been set - so a memory barrier needed.
	 */
	smp_mb();
5923
	if (mddev->reshape_backwards)
5924 5925 5926 5927
		conf->reshape_progress = raid5_size(mddev, 0, 0);
	else
		conf->reshape_progress = 0;
	conf->reshape_safe = conf->reshape_progress;
5928 5929 5930 5931
	spin_unlock_irq(&conf->device_lock);

	/* Add some new drives, as many as will fit.
	 * We know there are enough to make the newly sized array work.
5932 5933 5934 5935
	 * Don't add devices if we are reducing the number of
	 * devices in the array.  This is because it is not possible
	 * to correctly record the "partially reconstructed" state of
	 * such devices during the reshape and confusion could result.
5936
	 */
5937
	if (mddev->delta_disks >= 0) {
N
NeilBrown 已提交
5938
		rdev_for_each(rdev, mddev)
5939 5940 5941 5942
			if (rdev->raid_disk < 0 &&
			    !test_bit(Faulty, &rdev->flags)) {
				if (raid5_add_disk(mddev, rdev) == 0) {
					if (rdev->raid_disk
5943
					    >= conf->previous_raid_disks)
5944
						set_bit(In_sync, &rdev->flags);
5945
					else
5946
						rdev->recovery_offset = 0;
5947 5948

					if (sysfs_link_rdev(mddev, rdev))
5949
						/* Failure here is OK */;
5950
				}
5951 5952 5953 5954 5955
			} else if (rdev->raid_disk >= conf->previous_raid_disks
				   && !test_bit(Faulty, &rdev->flags)) {
				/* This is a spare that was manually added */
				set_bit(In_sync, &rdev->flags);
			}
5956

5957 5958 5959 5960
		/* When a reshape changes the number of devices,
		 * ->degraded is measured against the larger of the
		 * pre and post number of devices.
		 */
5961
		spin_lock_irqsave(&conf->device_lock, flags);
5962
		mddev->degraded = calc_degraded(conf);
5963 5964
		spin_unlock_irqrestore(&conf->device_lock, flags);
	}
5965
	mddev->raid_disks = conf->raid_disks;
5966
	mddev->reshape_position = conf->reshape_progress;
5967
	set_bit(MD_CHANGE_DEVS, &mddev->flags);
5968

5969 5970 5971 5972 5973
	clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
	clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
	set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
	set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
	mddev->sync_thread = md_register_thread(md_do_sync, mddev,
5974
						"reshape");
5975 5976 5977 5978
	if (!mddev->sync_thread) {
		mddev->recovery = 0;
		spin_lock_irq(&conf->device_lock);
		mddev->raid_disks = conf->raid_disks = conf->previous_raid_disks;
5979 5980 5981
		rdev_for_each(rdev, mddev)
			rdev->new_data_offset = rdev->data_offset;
		smp_wmb();
5982
		conf->reshape_progress = MaxSector;
5983
		mddev->reshape_position = MaxSector;
5984 5985 5986
		spin_unlock_irq(&conf->device_lock);
		return -EAGAIN;
	}
5987
	conf->reshape_checkpoint = jiffies;
5988 5989 5990 5991 5992
	md_wakeup_thread(mddev->sync_thread);
	md_new_event(mddev);
	return 0;
}

5993 5994 5995
/* This is called from the reshape thread and should make any
 * changes needed in 'conf'
 */
5996
static void end_reshape(struct r5conf *conf)
5997 5998
{

5999
	if (!test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) {
6000
		struct md_rdev *rdev;
6001 6002

		spin_lock_irq(&conf->device_lock);
6003
		conf->previous_raid_disks = conf->raid_disks;
6004 6005 6006
		rdev_for_each(rdev, conf->mddev)
			rdev->data_offset = rdev->new_data_offset;
		smp_wmb();
6007
		conf->reshape_progress = MaxSector;
6008
		spin_unlock_irq(&conf->device_lock);
6009
		wake_up(&conf->wait_for_overlap);
6010 6011 6012 6013

		/* read-ahead size must cover two whole stripes, which is
		 * 2 * (datadisks) * chunksize where 'n' is the number of raid devices
		 */
6014
		if (conf->mddev->queue) {
6015
			int data_disks = conf->raid_disks - conf->max_degraded;
6016
			int stripe = data_disks * ((conf->chunk_sectors << 9)
6017
						   / PAGE_SIZE);
6018 6019 6020
			if (conf->mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
				conf->mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
		}
6021 6022 6023
	}
}

6024 6025 6026
/* This is called from the raid5d thread with mddev_lock held.
 * It makes config changes to the device.
 */
6027
static void raid5_finish_reshape(struct mddev *mddev)
6028
{
6029
	struct r5conf *conf = mddev->private;
6030 6031 6032

	if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {

6033 6034 6035
		if (mddev->delta_disks > 0) {
			md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
			set_capacity(mddev->gendisk, mddev->array_sectors);
6036
			revalidate_disk(mddev->gendisk);
6037 6038
		} else {
			int d;
6039 6040 6041
			spin_lock_irq(&conf->device_lock);
			mddev->degraded = calc_degraded(conf);
			spin_unlock_irq(&conf->device_lock);
6042 6043
			for (d = conf->raid_disks ;
			     d < conf->raid_disks - mddev->delta_disks;
6044
			     d++) {
6045
				struct md_rdev *rdev = conf->disks[d].rdev;
6046 6047 6048 6049 6050
				if (rdev)
					clear_bit(In_sync, &rdev->flags);
				rdev = conf->disks[d].replacement;
				if (rdev)
					clear_bit(In_sync, &rdev->flags);
6051
			}
6052
		}
6053
		mddev->layout = conf->algorithm;
6054
		mddev->chunk_sectors = conf->chunk_sectors;
6055 6056
		mddev->reshape_position = MaxSector;
		mddev->delta_disks = 0;
6057
		mddev->reshape_backwards = 0;
6058 6059 6060
	}
}

6061
static void raid5_quiesce(struct mddev *mddev, int state)
6062
{
6063
	struct r5conf *conf = mddev->private;
6064 6065

	switch(state) {
6066 6067 6068 6069
	case 2: /* resume for a suspend */
		wake_up(&conf->wait_for_overlap);
		break;

6070 6071
	case 1: /* stop all writes */
		spin_lock_irq(&conf->device_lock);
6072 6073 6074 6075
		/* '2' tells resync/reshape to pause so that all
		 * active stripes can drain
		 */
		conf->quiesce = 2;
6076
		wait_event_lock_irq(conf->wait_for_stripe,
6077 6078
				    atomic_read(&conf->active_stripes) == 0 &&
				    atomic_read(&conf->active_aligned_reads) == 0,
6079
				    conf->device_lock);
6080
		conf->quiesce = 1;
6081
		spin_unlock_irq(&conf->device_lock);
6082 6083
		/* allow reshape to continue */
		wake_up(&conf->wait_for_overlap);
6084 6085 6086 6087 6088 6089
		break;

	case 0: /* re-enable writes */
		spin_lock_irq(&conf->device_lock);
		conf->quiesce = 0;
		wake_up(&conf->wait_for_stripe);
6090
		wake_up(&conf->wait_for_overlap);
6091 6092 6093 6094
		spin_unlock_irq(&conf->device_lock);
		break;
	}
}
6095

6096

6097
static void *raid45_takeover_raid0(struct mddev *mddev, int level)
6098
{
6099
	struct r0conf *raid0_conf = mddev->private;
6100
	sector_t sectors;
6101

D
Dan Williams 已提交
6102
	/* for raid0 takeover only one zone is supported */
6103
	if (raid0_conf->nr_strip_zones > 1) {
6104 6105
		printk(KERN_ERR "md/raid:%s: cannot takeover raid0 with more than one zone.\n",
		       mdname(mddev));
D
Dan Williams 已提交
6106 6107 6108
		return ERR_PTR(-EINVAL);
	}

6109 6110
	sectors = raid0_conf->strip_zone[0].zone_end;
	sector_div(sectors, raid0_conf->strip_zone[0].nb_dev);
6111
	mddev->dev_sectors = sectors;
D
Dan Williams 已提交
6112
	mddev->new_level = level;
6113 6114 6115 6116 6117 6118 6119 6120 6121 6122 6123
	mddev->new_layout = ALGORITHM_PARITY_N;
	mddev->new_chunk_sectors = mddev->chunk_sectors;
	mddev->raid_disks += 1;
	mddev->delta_disks = 1;
	/* make sure it will be not marked as dirty */
	mddev->recovery_cp = MaxSector;

	return setup_conf(mddev);
}


6124
static void *raid5_takeover_raid1(struct mddev *mddev)
6125 6126 6127 6128 6129 6130 6131 6132 6133 6134 6135 6136 6137 6138 6139 6140 6141 6142 6143 6144 6145
{
	int chunksect;

	if (mddev->raid_disks != 2 ||
	    mddev->degraded > 1)
		return ERR_PTR(-EINVAL);

	/* Should check if there are write-behind devices? */

	chunksect = 64*2; /* 64K by default */

	/* The array must be an exact multiple of chunksize */
	while (chunksect && (mddev->array_sectors & (chunksect-1)))
		chunksect >>= 1;

	if ((chunksect<<9) < STRIPE_SIZE)
		/* array size does not allow a suitable chunk size */
		return ERR_PTR(-EINVAL);

	mddev->new_level = 5;
	mddev->new_layout = ALGORITHM_LEFT_SYMMETRIC;
6146
	mddev->new_chunk_sectors = chunksect;
6147 6148 6149 6150

	return setup_conf(mddev);
}

6151
static void *raid5_takeover_raid6(struct mddev *mddev)
6152 6153 6154 6155 6156 6157 6158 6159 6160 6161 6162 6163 6164 6165 6166 6167 6168 6169 6170 6171 6172 6173 6174 6175 6176 6177 6178 6179 6180 6181 6182 6183
{
	int new_layout;

	switch (mddev->layout) {
	case ALGORITHM_LEFT_ASYMMETRIC_6:
		new_layout = ALGORITHM_LEFT_ASYMMETRIC;
		break;
	case ALGORITHM_RIGHT_ASYMMETRIC_6:
		new_layout = ALGORITHM_RIGHT_ASYMMETRIC;
		break;
	case ALGORITHM_LEFT_SYMMETRIC_6:
		new_layout = ALGORITHM_LEFT_SYMMETRIC;
		break;
	case ALGORITHM_RIGHT_SYMMETRIC_6:
		new_layout = ALGORITHM_RIGHT_SYMMETRIC;
		break;
	case ALGORITHM_PARITY_0_6:
		new_layout = ALGORITHM_PARITY_0;
		break;
	case ALGORITHM_PARITY_N:
		new_layout = ALGORITHM_PARITY_N;
		break;
	default:
		return ERR_PTR(-EINVAL);
	}
	mddev->new_level = 5;
	mddev->new_layout = new_layout;
	mddev->delta_disks = -1;
	mddev->raid_disks -= 1;
	return setup_conf(mddev);
}

6184

6185
static int raid5_check_reshape(struct mddev *mddev)
6186
{
6187 6188 6189 6190
	/* For a 2-drive array, the layout and chunk size can be changed
	 * immediately as not restriping is needed.
	 * For larger arrays we record the new value - after validation
	 * to be used by a reshape pass.
6191
	 */
6192
	struct r5conf *conf = mddev->private;
6193
	int new_chunk = mddev->new_chunk_sectors;
6194

6195
	if (mddev->new_layout >= 0 && !algorithm_valid_raid5(mddev->new_layout))
6196 6197
		return -EINVAL;
	if (new_chunk > 0) {
6198
		if (!is_power_of_2(new_chunk))
6199
			return -EINVAL;
6200
		if (new_chunk < (PAGE_SIZE>>9))
6201
			return -EINVAL;
6202
		if (mddev->array_sectors & (new_chunk-1))
6203 6204 6205 6206 6207 6208
			/* not factor of array size */
			return -EINVAL;
	}

	/* They look valid */

6209
	if (mddev->raid_disks == 2) {
6210 6211 6212 6213
		/* can make the change immediately */
		if (mddev->new_layout >= 0) {
			conf->algorithm = mddev->new_layout;
			mddev->layout = mddev->new_layout;
6214 6215
		}
		if (new_chunk > 0) {
6216 6217
			conf->chunk_sectors = new_chunk ;
			mddev->chunk_sectors = new_chunk;
6218 6219 6220
		}
		set_bit(MD_CHANGE_DEVS, &mddev->flags);
		md_wakeup_thread(mddev->thread);
6221
	}
6222
	return check_reshape(mddev);
6223 6224
}

6225
static int raid6_check_reshape(struct mddev *mddev)
6226
{
6227
	int new_chunk = mddev->new_chunk_sectors;
6228

6229
	if (mddev->new_layout >= 0 && !algorithm_valid_raid6(mddev->new_layout))
6230
		return -EINVAL;
6231
	if (new_chunk > 0) {
6232
		if (!is_power_of_2(new_chunk))
6233
			return -EINVAL;
6234
		if (new_chunk < (PAGE_SIZE >> 9))
6235
			return -EINVAL;
6236
		if (mddev->array_sectors & (new_chunk-1))
6237 6238
			/* not factor of array size */
			return -EINVAL;
6239
	}
6240 6241

	/* They look valid */
6242
	return check_reshape(mddev);
6243 6244
}

6245
static void *raid5_takeover(struct mddev *mddev)
6246 6247
{
	/* raid5 can take over:
D
Dan Williams 已提交
6248
	 *  raid0 - if there is only one strip zone - make it a raid4 layout
6249 6250 6251 6252
	 *  raid1 - if there are two drives.  We need to know the chunk size
	 *  raid4 - trivial - just use a raid4 layout.
	 *  raid6 - Providing it is a *_6 layout
	 */
D
Dan Williams 已提交
6253 6254
	if (mddev->level == 0)
		return raid45_takeover_raid0(mddev, 5);
6255 6256
	if (mddev->level == 1)
		return raid5_takeover_raid1(mddev);
6257 6258 6259 6260 6261
	if (mddev->level == 4) {
		mddev->new_layout = ALGORITHM_PARITY_N;
		mddev->new_level = 5;
		return setup_conf(mddev);
	}
6262 6263
	if (mddev->level == 6)
		return raid5_takeover_raid6(mddev);
6264 6265 6266 6267

	return ERR_PTR(-EINVAL);
}

6268
static void *raid4_takeover(struct mddev *mddev)
6269
{
D
Dan Williams 已提交
6270 6271 6272
	/* raid4 can take over:
	 *  raid0 - if there is only one strip zone
	 *  raid5 - if layout is right
6273
	 */
D
Dan Williams 已提交
6274 6275
	if (mddev->level == 0)
		return raid45_takeover_raid0(mddev, 4);
6276 6277 6278 6279 6280 6281 6282 6283
	if (mddev->level == 5 &&
	    mddev->layout == ALGORITHM_PARITY_N) {
		mddev->new_layout = 0;
		mddev->new_level = 4;
		return setup_conf(mddev);
	}
	return ERR_PTR(-EINVAL);
}
6284

6285
static struct md_personality raid5_personality;
6286

6287
static void *raid6_takeover(struct mddev *mddev)
6288 6289 6290 6291 6292 6293 6294 6295 6296 6297 6298 6299 6300 6301 6302 6303 6304 6305 6306 6307 6308 6309 6310 6311 6312 6313 6314 6315 6316 6317 6318 6319 6320 6321 6322 6323 6324 6325 6326 6327 6328 6329 6330 6331 6332 6333
{
	/* Currently can only take over a raid5.  We map the
	 * personality to an equivalent raid6 personality
	 * with the Q block at the end.
	 */
	int new_layout;

	if (mddev->pers != &raid5_personality)
		return ERR_PTR(-EINVAL);
	if (mddev->degraded > 1)
		return ERR_PTR(-EINVAL);
	if (mddev->raid_disks > 253)
		return ERR_PTR(-EINVAL);
	if (mddev->raid_disks < 3)
		return ERR_PTR(-EINVAL);

	switch (mddev->layout) {
	case ALGORITHM_LEFT_ASYMMETRIC:
		new_layout = ALGORITHM_LEFT_ASYMMETRIC_6;
		break;
	case ALGORITHM_RIGHT_ASYMMETRIC:
		new_layout = ALGORITHM_RIGHT_ASYMMETRIC_6;
		break;
	case ALGORITHM_LEFT_SYMMETRIC:
		new_layout = ALGORITHM_LEFT_SYMMETRIC_6;
		break;
	case ALGORITHM_RIGHT_SYMMETRIC:
		new_layout = ALGORITHM_RIGHT_SYMMETRIC_6;
		break;
	case ALGORITHM_PARITY_0:
		new_layout = ALGORITHM_PARITY_0_6;
		break;
	case ALGORITHM_PARITY_N:
		new_layout = ALGORITHM_PARITY_N;
		break;
	default:
		return ERR_PTR(-EINVAL);
	}
	mddev->new_level = 6;
	mddev->new_layout = new_layout;
	mddev->delta_disks = 1;
	mddev->raid_disks += 1;
	return setup_conf(mddev);
}


6334
static struct md_personality raid6_personality =
6335 6336 6337 6338 6339 6340 6341 6342 6343 6344 6345 6346 6347 6348
{
	.name		= "raid6",
	.level		= 6,
	.owner		= THIS_MODULE,
	.make_request	= make_request,
	.run		= run,
	.stop		= stop,
	.status		= status,
	.error_handler	= error,
	.hot_add_disk	= raid5_add_disk,
	.hot_remove_disk= raid5_remove_disk,
	.spare_active	= raid5_spare_active,
	.sync_request	= sync_request,
	.resize		= raid5_resize,
6349
	.size		= raid5_size,
6350
	.check_reshape	= raid6_check_reshape,
6351
	.start_reshape  = raid5_start_reshape,
6352
	.finish_reshape = raid5_finish_reshape,
6353
	.quiesce	= raid5_quiesce,
6354
	.takeover	= raid6_takeover,
6355
};
6356
static struct md_personality raid5_personality =
L
Linus Torvalds 已提交
6357 6358
{
	.name		= "raid5",
6359
	.level		= 5,
L
Linus Torvalds 已提交
6360 6361 6362 6363 6364 6365 6366 6367 6368 6369 6370
	.owner		= THIS_MODULE,
	.make_request	= make_request,
	.run		= run,
	.stop		= stop,
	.status		= status,
	.error_handler	= error,
	.hot_add_disk	= raid5_add_disk,
	.hot_remove_disk= raid5_remove_disk,
	.spare_active	= raid5_spare_active,
	.sync_request	= sync_request,
	.resize		= raid5_resize,
6371
	.size		= raid5_size,
6372 6373
	.check_reshape	= raid5_check_reshape,
	.start_reshape  = raid5_start_reshape,
6374
	.finish_reshape = raid5_finish_reshape,
6375
	.quiesce	= raid5_quiesce,
6376
	.takeover	= raid5_takeover,
L
Linus Torvalds 已提交
6377 6378
};

6379
static struct md_personality raid4_personality =
L
Linus Torvalds 已提交
6380
{
6381 6382 6383 6384 6385 6386 6387 6388 6389 6390 6391 6392 6393
	.name		= "raid4",
	.level		= 4,
	.owner		= THIS_MODULE,
	.make_request	= make_request,
	.run		= run,
	.stop		= stop,
	.status		= status,
	.error_handler	= error,
	.hot_add_disk	= raid5_add_disk,
	.hot_remove_disk= raid5_remove_disk,
	.spare_active	= raid5_spare_active,
	.sync_request	= sync_request,
	.resize		= raid5_resize,
6394
	.size		= raid5_size,
6395 6396
	.check_reshape	= raid5_check_reshape,
	.start_reshape  = raid5_start_reshape,
6397
	.finish_reshape = raid5_finish_reshape,
6398
	.quiesce	= raid5_quiesce,
6399
	.takeover	= raid4_takeover,
6400 6401 6402 6403
};

static int __init raid5_init(void)
{
6404
	register_md_personality(&raid6_personality);
6405 6406 6407
	register_md_personality(&raid5_personality);
	register_md_personality(&raid4_personality);
	return 0;
L
Linus Torvalds 已提交
6408 6409
}

6410
static void raid5_exit(void)
L
Linus Torvalds 已提交
6411
{
6412
	unregister_md_personality(&raid6_personality);
6413 6414
	unregister_md_personality(&raid5_personality);
	unregister_md_personality(&raid4_personality);
L
Linus Torvalds 已提交
6415 6416 6417 6418 6419
}

module_init(raid5_init);
module_exit(raid5_exit);
MODULE_LICENSE("GPL");
6420
MODULE_DESCRIPTION("RAID4/5/6 (striping with parity) personality for MD");
L
Linus Torvalds 已提交
6421
MODULE_ALIAS("md-personality-4"); /* RAID5 */
6422 6423
MODULE_ALIAS("md-raid5");
MODULE_ALIAS("md-raid4");
6424 6425
MODULE_ALIAS("md-level-5");
MODULE_ALIAS("md-level-4");
6426 6427 6428 6429 6430 6431 6432
MODULE_ALIAS("md-personality-8"); /* RAID6 */
MODULE_ALIAS("md-raid6");
MODULE_ALIAS("md-level-6");

/* This used to be two separate modules, they were: */
MODULE_ALIAS("raid5");
MODULE_ALIAS("raid6");